"She is in a cell block with people who have been convicted of dangerous felonies – murderers – and of course, she wants to get out," the source tells PEOPLE. "She is not getting any special treatment of any kind ... She's behind glass [in the visiting area], and her family and friends can't touch her."
The actress, now in her third day of confinement, is said to have left her father Michael off the list of potential visitors she gave to prison officials. "No one at the jail will even tell her that he's there, if he does come. He will not be visiting her," the source says.
Asked how Lohan is faring, the source replied: "She looks beautiful. She is just doing what she has got to do right now." Lohan's lawyer, Shawn Chapman Holley, echoed that, telling PEOPLE: "She's actually doing quite well."
Lohan's mother Dina and sister Ali, along with business manager Lou Taylor visited Lohan for about 30 minutes on Wednesday. A family friend tells PEOPLE that Dina and Ali are "devastated" but resilient.
"Their faith is keeping them strong," the friend says. "Their faith and the thought that this is going to be over soon and that Lindsay is going to be okay."
Lindsay calls Dina "Mommy" and looks up to her, often saying, "My Mommy is so strong," the friend adds.
Lohan is expected to serve about two weeks of her 90-day sentence for violating probation in a DUI case.
Reporting by ALICIA DENNIS and KEN LEE