"I'm not taking this as a joke," Lohan said. "It's my life and it's my career."
Lohan's probation report, released Thursday, shows that six of the actress's drug screenings since may were clean.
According to the court documents, Lohan tested positive for amphetamines and opiates in those tests, but those were not violations of her probation because the chemicals are found in her prescription medications.
Now something small enough to fit on a fingernail is causing even more grief for the troubled actress.
Too small for the judge to see, but clearly visible with a zoom lens was an expletive on top of her colorful nail polish. It's unclear exactly how long the fingernail profanity has been there or if she was sending a defiant message to the court while sobbing her explanation for unintentionally violating her probation.
Thursday afternoon, Lohan Tweeted that her nails were a joke: "It had nothing to do w/court.. it's an airbrush design from a stencil xx."
Just how long Lohan will spend in jail is up to L.A. County Sheriff Lee Baca.
The longer Lohan spends in jail, the bigger the impact on Hollywood and other industries.
Lohan may not be able to promote her latest film called "Machete," set to be released in September. She has also been cast as the lead in, "Inferno: A Linda Lovelace Story." Production on that film would also be delayed.
And Lohan's new fashion line, 6126, is ready to ship its 280-piece collection to department stores this month.
On The Red Carpet caught up with Lohan's former boyfriend, actor Wilmer Valderrama.
"I just hope she's OK and she'll be great," Valderrama said.
There is a good chance Lohan won't have to serve her full sentence. Overcrowded L.A. County jails and good behavior could mean she spends less than a month behind bars.
"Female inmates that have what are known as non-violent offenses - misdemeanors - if they are eligible will do in general about 25 percent of their sentence," said Steve Whitmore, spokesman for the L.A. County Sheriff's Department.
The 24-year-old had been ordered to attend alcohol-education classes after pleading guilty to using cocaine and pleading no contest to driving under the influence of alcohol in 2007.
Lohan missed seven weeks of the program. Her poor attendance will now send her to jail on a 90-day sentence.
It was a much harsher sentence than prosecutors had requested, and some legal experts say it is too stiff.
"The idea of 90 days followed up by another 90 days in a program for a total of 180 days in some ways she was probably better off just telling the judge 'take your probation and stick it, just give me the maximum and I'll let the sheriff just walk me out the back door,'" said defense attorney Mark Geragos.
When Lohan begins serving her sentence on July 20, she'll be in a wing separate from the other roughly 2,100 inmates at Century Regional Detention Facility in Lynwood. It's the same jail where Paris Hilton served 23 days three years ago and where Nicole Richie spent only 82 minutes.
Once Lohan is out of the county jail, she will have to check into a substance-abuse rehab facility, where she will spend another 90 days.
Calls to her attorney seeking a comment on the fingernail profanity have not yet been returned.