POOLSources say Lindsay Lohan, who is set to begin her 90-day jail sentence Tuesday, is a 'nervous, fidgety' mess.

LOS ANGELES - Lindsay Lohan was reportedly scrambling for a new lawyer Monday night as she prepared to go to jail Tuesday.

Famed defense attorney Robert Shapiro - who was expected to make an eleventh-hour request for a judge to reduce or restructure LiLo's 90-day sentence - walked out on the troubled actress Monday night, TMZ.com reported. 

It was not immediately clear why Shapiro, a member of O.J. Simpson's Dream Team, quit on Lohan. 

Shapiro refused to comment Monday night, but sounded like he was still preparing to rep Lohan in court. 

"The only comments I will make will be in open court," he e-mailed the Daily News. 

Lohan, 24, last week checked into a sober living facility founded by Shapiro, whose son died in 2005 from a drug overdose. 

Shapiro agreed to take on the "Mean Girls" star's case on the condition she accept a "requirement of jail."

Lohan's previous attorney, Shawn Chapman Holley, parted ways with the starlet this month without explanation. 

As her final hours of freedom ticked down, Lohan seemed to be coming to terms with her fate. 

"The only 'bookings' that I'm familiar with are Disney Twitter page Monday night. 

Lohan has been ordered jailed for 90 days for violating her probation on her DUI case, but she'll probably serve only a quarter of that time because of overcrowding. 

But even a few days at the Century Regional Detention Facility in Los Angeles was enough to crack one ex-inmate. 

"I was depressed and crying every day," Shirley Alexander, 37, of Hawthorne, Calif., told the Daily News. "I was counting the bricks in the walls." 

Lohan is already "a nervous, fidgety mess," a source told People.com. "She has not been able to sleep and has barely been eating." 

Read more: http://www.nydailynews.com/gossip/2010/07/20/2010-07-20_lindsay_lohans_lawyer_reportedly_quits.html#ixzz0uDrB8hyK