The singer has been 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 for pressuring her to enter the program. She feels she was ambushed."

Since entering the clinic, Britney has been seen reading Brooke Shields'
book 'Down Came the Rain' about the actress' own experience with postpartum
depression following the birth of her first daughter, Rowan Francis.

Last week, NOTW UK reported, that the troubled singer tried to hang herself with a bedsheet before pleading with her estranged husband to give her another baby. According to a source , the crazy singer wrote the number of the beast, 666, on her shaved head before running round the clinic screaming "I am the Antichrist!" .
"Later that night she tried to kill herself," a friend told NOTW. "She attached a sheet to a light and tied it around her neck. Paramedics were called, but luckily she was unhurt."

Meanwhile, the 'Toxic' singer's stint in rehab has brought her family and Kevin Federline's family closer -
despite the couple's impending divorce - to support Britney and care for her
two young sons.

A source told People magazine: "Everyone is making comments how sad it is
that it took this to get everyone together.
"There was a lot of distance between the families but it seems now they all
have a common goal, which is to help Britney get better."
Kevin has been looking after 18-month-old Sean Preston and six-month-old
Jayden James, with the help of both families, since his estranged wife
checked into rehab

In other news, Simon Cowell thinks Britney Spears needs to get off her high horse.

The American Idol judge is dismissing the pop star's recent meltdown, writing off her rehab stint as a trendy indulgence.

"It's very fashionable to be in rehab," Cowell, 47, told the London Mirror via MSNBC's The Scoop.

"This whole thing is a total indulgence. Britney and Robbie need to get a grip. We've allowed these people to feel sorry for themselves. I don't know what's going on in Britney's head but my attitude is I couldn't care less. She should go back and live with her mum for six months."