Lindsay Lohan acknowledged through Twitter postings Friday night that she failed a recent drug test, but the actress said she’s “working hard to overcome” her drug addiction.

Lohan’s supervised probation for a 2007 drunken driving conviction requires frequent drug tests. The judge warned her last month any failure could send her back to jail.

“Regrettably, I did in fact fail my most recent drug test and if I am asked, I am prepared to appear before judge Fox next week as a result,” Lohan tweeted Friday evening.

She spent 23 days in a court-ordered drug rehab program last month, which followed a 13-day jail stint imposed when a Los Angeles judge ruled that Lohan violated her probation.

Judge Elden Fox, who took over Lohan’s case when she was released, imposed a new set of rules for her to follow until November. It included weekly counseling sessions for alcohol and drug rehab, random drug tests and behavioral therapy.

Lohan’s lawyer did not respond to CNN requests for comment Friday. A spokesman for the Los Angeles County district attorney also declined to comment.

No new court date has been announced for Lohan to face Judge Fox concerning the failed drug test.

“Substance abuse is a disease, which unfortunately doesn’t go away overnight,” Lohan tweeted. “I am working hard to overcome it and am taking positive steps.”

Lohan tweeted that she was “doing what I must do to prevent any mishaps in the future.”

“This was certainly a setback for me, but I am taking responsibility for my actions and I’m prepared to face the consequences,” she tweeted.

Lohan made fun of her substance abuse troubles in a backstage skit broadcast during last Sunday’s MTV Video Music Awards.

She appeared with show host Chelsea Handler, who was wearing an alcohol-detection bracelet like the one Lohan recently wore.

“Wake up, Handler, pull it together,” Lohan said as she slammed Handler against a wall. “You’re a menace. Do you think anyone will work with a drunk? Take it from me, they don’t.”

Lindsay Lohan is out of jail – but she isn't happy.

"Lindsay is very upset that the judge ordered her to go straight to rehab," a source tells PEOPLE.

The actress, 24, was released from a Lynwood, Calif., jail early Monday morning after serving 13 full days of a 90-day sentence for violating probation in a DUI case. She was directly sent to rehab at UCLA Medical Center, where she is required to complete a three-month inpatient stint, according to Judge Marsha Revel's sentencing order.

Though her mom Dina and younger sister Ali met up with Lohan at UCLA on Monday, "[Lindsay] feels that she deserved to spend a day with her family after she behaved well in jail," says the source.

Lohan, the source adds, is feeling "depressed." "[She] is having a difficult time accepting that she will be in rehab for the next three months," the source says. "She still doesn't think that she needs any help."

Between fielding questions about the economy, Afghanistan, and racial tensions in the U.S., President Barack Obama got down to the important stuff on The View Thursday: the alleged rants of Mel Gibson, the jail term of Lindsay Lohan and Jersey Shore's Nicole "Snooki" Polizzi – and the burning question of should she run for mayor of Wasilla, Alaska.

Quizzed by Joy Behar in a "lightening" round, Obama was asked if he knew if Lohan is in jail. "I actually know that, yes," the President responded.

But Snooki stumped him. "Should Snooki run as mayor of Wasilla?" Behar asked. Obama, laughing, responded, "I gotta admit, I don't know who Snooki is."

On his final question, the Chief Executive was thrown – or simply being diplomatic – when Behar inquired if he thought Gibson needs "anger management."

"I … I …," the President stuttered and then joked, "Let me answer the Afghanistan question!" He informed the panel he "hadn't seen the tapes."

Obama, who has two young daughters, Sasha and Malia, said he'd met Justin Bieber and thought he was "a very nice young man."

On a more serious note, the President discussed unemployment with the conservative Elisabeth Hasselbeck and racism with Whoopi Goldberg. Ultimately, he said, he remains optimistic the economy will improve, and acknowledged that "I'm not perfect, my administration's not perfect."

Obama also touched on the fact he was not invited to Chelsea Clinton's wedding and said that when the time comes he also intends to keep Sasha and Malia's weddings private – and therefore probably wouldn't be inviting any of the ladies on The View.

As far as reports go, Lindsay Lohan is eating the same meals as regular inmates at the Century Regional Detention Facility. But that doesn't mean she's being entirely treated like the others.

"She's not treated like if it was anyone else going to jail," Maria Medina, a relative of an inmate at Lohan's jail tells PEOPLE. "Like, if they even want to bring her new clothes or bring her anything, they put the whole facility on lockdown. It happens all the time."

Medina, 40, says residents at the jail, based in Lynwood, Calif., find it unfair that someone they're not even allowed to see is exerting so much control over their stay.

"All the inmates are sick of Lindsay," Medina says. "It's almost like Lindsay Lohan's here, but she's not. Like if she even moves, they put the whole facility on lockdown. It happens all the time. For example, just yesterday [Friday], Lindsay had to go to the mini-clinic, and the whole place was on lockdown again."

Los Angeles Sheriff's spokesman Steve Whitmore denied Medina's claim. "It's business as usual. Lindsay's getting no special treatment," he told PEOPLE on Saturday. He also said there is no such thing as "lockdowns."

As far as Lohan is concerned, she's now apparently in a much better state of mind than earlier this week.

"[Lindsay's] doing well, she's doing fine," Lohan's lawyer Shawn Chapman Holley tells PEOPLE. "Her outlook is definitely more positive."

Despite speculation that Lohan was given exemptions when it came to visitation limits, Holley told reporters her client is playing by the rules, saying,"[Her family's] not allowed any more visits this week."

Whitmore earlier this week told PEOPLE that Lohan received her visits during the week to avoid disrupting other families visiting on the weekend with ensuing TV crews and photographers.

Shawn Chapman Holley is going to be by Lindsay Lohan's side in court this morning, representing her after Robert Shapiro bailed on LiLo.

Holley quit earlier this month, because Lindsay was an uncontrollable client. But now Lindsay is in a pinch, and Holley is stepping up. Sources say Lindsay is furious at Shapiro, feeling as if he totally used her to get publicity for his sober living house. She believes that is the only reason he agreed to rep her and sold her a bill of goods. We've learned Holley is supposed to be in court in the Juan-Carlos Cruz attempted murder case at the same time Lindsay's case is heard. We're told Holley is going to have the Cruz case delayed so she can be with Lindsay. As for Lindsay, we're told she's terrified but on board with the plan today.

Lindsay Lohan, who has been ordered to report to jail by next Tuesday, has checked herself into Pickford Lofts, a sober-living house in Los Angeles founded by famed defense attorney Robert Shapiro.

The troubled actress, 24, arrived on Wednesday afternoon and was still at the facility on Thursday, sources confirm to PEOPLE. She was sentenced to 90 days in jail on July 6 for violating her probation in a DUI case.

Lohan's former girlfriend, Samantha Ronson, who recently defended her ex against attacks from Joan Rivers, visited her at the home last night.

Shapiro, 67, a celebrated lawyer best known for successfully defending O.J. Simpson in his murder trial in the mid-'90s, has been involved in rehab facilities since his son Brent died of a drug overdose in 2005. He also created The Brent Shapiro Foundation to help people deal with drug and alcohol problems, and speculation is that he will take over Lohan's case.

"Robert Shapiro is not yet Lindsay's official lawyer," a source tells PEOPLE, adding that Shapiro connected with Lohan after being contacted by one of her acquaintances. While in the facility, Lohan will be meeting with addiction specialists, so, the source adds, "Shapiro can assess Lindsay's situation before he makes an announcement that he's her lawyer."

Her voluntary admission into the sober house was done in the hopes that her jail sentence would get modified.

"She's trying to make an effort," the source says. "The hope is that the judge either reduces the sentence or tosses it out have have Lindsay stay in a facility instead of jail. The hope is that the judge sees Lindsay getting treatment and put her in an inpatient [rehab] program for 90 days instead of jail. Lindsay is not trying to fight or appeal the sentence, but adjust it."

Adds the source: "She had an opportunity to get into a sober house, so she checked herself into his sober living facility, and he's going to see how she behaves."

And while Shapiro evaluates Lohan's behavior, the source says, she really "needs that help. she has mental health issues that stem back from her father, and the abuse that she watched her mom endure."

Lindsay Lohan is gettin’ gangsta in preparation for her stint in jail. She got on Twitter and starting bombing her dad and Joan Rivers. She even quoted 50 cent on they a**es! Pop it for the hilarity.

Lindsay revving up to go to the bing. She’s gettin’ lesbooed up with Samantha Ronson and listening to 50 cent in preparation.

According to The NY Daily News, Lohan, fired back at Joan Rivers via Twitter on Tuesday after the comedienne cracked a few jokes about the actress on her own Twitter page last Friday.

“Joan Rivers and her ‘stargument’ make me believe that she and Michael Lohan are a match made in heaven,” Lohan tweeted about Rivers and her estranged father.

In her next Tweet, the actress added a cyber-jab at Dr. Drew Pinsky of “Celebrity Rehab,” who once said the troubled starlet needed to get arrested in order to get better.

“All [Michael] needs is [Joan's] botox doctor. ‘Dr.’ Drew – any ideas? Botox rehab reality show?” LiLo wrote.

“In the words of 50 cent,” she further tweeted, “You shouldn’t throw stones if you live in a glass house and if you got a glass jaw, you should watch yo mouth.”

Her Twitter taunts come after Rivers, 77, made some jokes at Lohan’s expense on Twitter last week.

“Lindsay Lohan is so dumb. Her idea of being sworn in is cursing at the judge,” she wrote, referring to Lohan’s F-word manicure.

“I was just reading about the new Lindsay Lohan diet, which is all liquid. 80 Proof,” Rivers continued.

She also quipped, “Lindsay Lohan said she wouldn’t mind being under oath because she thought Oath was a Norwegian ski instructor.”

Although Lohan is just now responding to the comedienne’s tweets, Samantha Ronson came to her ex-girlfriend’s defense almost immediately.

“Hey Joan Rivers- you have collagen older than Lindsay, pick on someone your own age, oh wait, I guess people that old can’t hear,” she tweeted on Friday.

Nobody wants to go to jail, and as a 90-day sentence looms for Lindsay Lohan, her lawyer is calling the punishment unjust.

"Ms. Lohan and I are extremely disappointed in the sentence handed down by Judge Revel. We believe that the penalty is far harsher than what others would have received under similar circumstances," Lohan's attorney, Shawn Chapman Holley, who's based in Santa Monica at the firm Kinsella Weitzman Iser Kump & Aldisert, said in a statement Thursday.

"The reality is that Ms. Lohan, like most defendants, had to balance work commitments with court requirements," the statement continues. "To be punished so severely for doing so, particularly in light of the fact that she substantially complied with each of her probationary conditions, is harsh and unfair."

That said, Holley added, "Ms. Lohan is prepared to serve her jail time and to comply with the Court's orders." Her 90-day sentence is set to begin July 20.

Holley also addressed the brewing controversy over a manicure Lohan sported with an explicit message.

"With respect to Ms. Lohan's nails, the fact is, the words could barely be seen by the naked eye," Holley says. "That a courtroom camera, purportedly there to accurately chronicle the proceedings, would use a telephoto lens to zoom in as it did to Ms. Lohan's fingernail is a commentary on the entire issue."

If it was a performance, it deserved at least a nomination. Instead, it earned her one of the worst pans of her life.

Staring down a terrifying stint in a cramped Los Angeles County jail cell, Lindsay Lohan broke into tears Tuesday as she pleaded with a Beverly Hills judge for understanding.

"I did everything I was told to do, I thought I was being compliant," Lohan, 24, cried as she tried to explain that she didn't knowingly violate her probation in a DUI case by missing weekly alcohol-education classes. "I'm not taking this as a joke, it's my life and career. I don't want you to think I don't respect you and your terms."

In the audience section, her father Michael Lohan – himself no stranger to courtrooms due to his own battles with the bottle – also wept, as did Lindsay's 16-year-old sister Ali.

In the end, the tears and tissues and smeared mascara held no sway. Superior Court Judge Marsha Revel sentenced Lohan to 90 days in jail and ordered the troubled actress to spend another three months in rehab within two days after she's sprung from jail.

"I couldn't have been more clear [about my orders]," Revel said. "There are no excuses."

Lohan was ordered to surrender to the court on July 20 to begin her sentence, probably at the women's Century Regional Detention Facility in Lynwood, Calif., where she previously served just 84 minutes of a 24-hour sentence nearly three years ago.

Upon her release from rehab, Lohan will still be forbidden from consuming alcohol until the remainder of her probation term which ends in August 2011.

Despite her three-month sentence, Lohan may only end up serving a fraction of the term due to the L.A. Sheriff's long-standing policy of releasing non-violent offenders early due to severe jail overcrowding. It's unclear if the judge will forbid an early release.

Lohan had been treading on thin ice with the court since October, when Judge Revel sternly warned the actress not to create any more mishaps in her case otherwise she'd face jail time.

Since then, Lohan pulled a no-show at a mandatory progress review hearing in May, claiming her passport was stolen while at the Cannes Film Festival. She was fitted with a SCRAM alcohol-monitoring bracelet as a result and has been subject to random drug testing.

Two weeks later, the SCRAM bracelet was set off, leading to Lohan's third arrest warrant in the case, although her attorney later claimed she tested negative for alcohol.

First the bad news: Lindsay Lohan still faces the possibility of jail. The good news? At least she can make her next birthday bash.

Tuesday's hearing on whether the star violated her probation in her DUI case kicked off with prosecutor Danette Meyers telling Judge Marsha Revel that she had been unable to procure Lohan's records from her treatment facility. After some back and forth, Lohan's lawyer, Shawn Chapman Holley, told Her Honor she did not object to the program's records being turned over to the D.A.

After a brief break, the two sides then argued whether Lohan's SCRAM bracelet alert a month ago was not just a violation of bail but also a violation of Lohan's probation.

"I believe it's a violation of probation because the court ordered her not to drink alcohol," said Meyers. "We have witnesses to prove she had alcohol in her system...We are also prepared to put on evidence the device was tampered with."

Holley, on the other hand, told the judge she was not prepared to call experts to testify about the reliability of the device or lack thereof.

The SCRAM issue quickly became moot, however, when Revel ruled that despite the court previously feeling that the bracelet's results (which showed the actress with a blood alcohol level of .03 when she supposedly was in violation) were credible, such evidence would not be admissible in today's proceeding.

"The court felt they were reliable enough to issue a bench warrant and double the bail," said the judge. "[But] I'm not going to allow as part of the probation violation hearing anything about the SCRAM...The violation of the court is whether or not she followed the court's orders in going to the program once a week."

That pretty much means Lohan's freedom now hinges on whether she attended her alcohol education classes.

Meyers subsequently called witnesses for the prosecution to prove she did not. Among those was Cherie Marshall, cofounder of the Right On Program, the treatment facility Lohan enrolled in.

The assistant D.A. used her testimony to show that Lohan had eight unexcused absences since she began attending weekly sessions Dec. 15 at the behest of a verbal order from Revel, given over the phone.

Marshall admitted that after Lohan's first class on Dec. 16, the thesp did not attend until Dec. 30.

"Did you think that I didn't mean it?" asked Judge Revel regarding the reason why Lohan was not following her order to attend once a week.

Marshall replied it was never her idea not to comply with a court order. Marshall testified that she did not believe Lohan was officially ordered to attend the program once a week because no official written order was ever sent.

"If a judge calls, would you take it seriously?" asks Judge Revel.

Marshall said Revel's call was the first one she has ever received from a judge directly. She also noted that the "chaos" of Lohan's celebrity prompted her to have to reschedule a number of group sessions to maintain the privacy of the other group participants.

Meyers subsequently ran down the dates of other classes Lindsay had missed and her excuses, including May 17, when she was partying it up at the Cannes Film Festival.

When asked by the prosecutor if Lohan was being truthful about her absences, Marshall replied, "No."

The May 17 class Lohan skipped was right around the time she also failed to show up for a probation hearing, citing a stolen passport, displeasing Revel and prompting her to issue an arrest warrant. And when she finally did appear the following week, she was late.

For today's session, the erstwhile Freaky Friday star, who turned 24 last Friday, showed up early this time around. Clad in a black turtleneck and gray slacks, she sat quietly at the defense table as both attorneys went at it.

On a separate matter, Judge Revel also denied Michael Lohan's request to meet with her in private in chambers. Instead, she said Lindsay's father can submit a letter that can be shown to both parties and Lohan.

The hearing adjourned until 1:30 p.m. PT.

E! News meanwhile has learned that Lohan has planned yet another birthday soiree tonight, this one an "official" party at Drai's Hollywood (and let's hope it's one where the staff doesn't get punchy), though according to a source, it all depends on what happens today in court.

Story developing...

Dina Lohan, mother of Lindsay has chimed in telling people, "I think it's a great idea for her, but Lindsay has two movies coming up, so I don't know if Lindsay has time. it may conflicet her schedule."

Lindsay is currently wearing a court ordered alcohol-monitoring bracelet on her ankle. She is not allowed to leave L.A. either. However, Lindsay plus Donald would make fore some good TV. *fingers crossed*