Britney Spears has been in rehab for two weeks.

Which is good. But doctors are still concerned about her condition.

"They're in shock at what bad shape she's in," says an insider.

Another source says that since Spears checked in to Promises Treatment Center in Malibu, Calif., on February 21 (for the second time, after bailing after 24 hours the first time), the troubled singer "has been getting in tons of trouble."

In fact, the 25-year-old mother of Sean Preston and Jayden James has been formally reprimanded for making cellphone calls, has left the facility to shop, and now she wants to leave rehab for good.

"She's convinced she's suffering from postpartum depression and does not think she has an alcohol or drug problem," the source says.

"She's angry at her family and her manager, Larry Rudolph, for pressuring her to enter the program. She feels she was ambushed."

Never mind that Kevin Federline and the rest of the family members who "ambushed" Brit are worried sick about her - and her infant children.

However, according to another reformed wild child, Courtney Love, whether or not Britney Spears gets better is entirely up to Britney Spears:

"You don't stop until you want to stop," Love said. "You can't make someone stop."

The fact that Courtney Love and Daniel Baldwin are offering advice to our girl is somewhat amusing to T.H. Gossip. But hey, they mean well.