Apparently being locked up in rehab isn't even enough for Lindsay Lohan to lay off the drugs. Reports are now out that Lohan has failed drug tests while in rehab at the Cirque Lodge in Utah.

Lohan was allegedly dragged into the director's office and forced to take the test, which came back positive. Lohan, 21, was then warned that if she does not stay clean and sober, she will be tossed from the rehab center.

According to a source, "During the test Lindsay screamed and cursed at the medical director before storming out of the room."

And according to other reports, this isn't Lindsay's first problems at the Cirque Lodge. She was reportedly caught having sex in a bathroom stall with a male patient, and refuses to do any chores.

Her latest indiscretion comes just one week after pleading no contest to drunk driving and cocaine possession. She got off rather easy, receiving a sentence of just one day in jail. However, part of her plea bargain hinges on her completion of the rehab program, and if she fails to complete it, she could face a lengthy jail sentence.

In other words, it's time for her to shape up, or do some hard time.