Demi Lovato revealed a lot of her personal demons in her 'Stay Strong' documentary, and she's opening up even more in a new interview with U.K. magazine Fabulous. Lovato talks about her descent into the dark life of her eating disorder, self-harm and substance abuse.

What seems to be the root cause of Lovato's issues? Perhaps her parents' divorce. They split when she was 2 years old (she's still estranged from her father), so she never had a stable, secure home life. As a result, she threw herself into her work to distract herself from her emotional problems -- but it wound up burning her out and making them worse. "I went from movie to album to touring to television and back," she said. "Being in the limelight wasn't the root of my problems, but it didn't help. I never took more than two weeks off in four years and it caught up with me."

Lovato says that with stardom came bullies at school. "They called me a w---- and told me I was fat and ugly," she vented. "I shouldn't have listened, but I took it to heart and it hurt. I thought maybe I didn't have friends because I was too fat."

"There were times I wish I'd been a normal teenager so I could make mistakes and not be scrutinized," she said, "but I don't mourn the childhood I never had. I'd rather have been traveling the world and making albums than at high school." Lovato also says that the bullies who tormented her are the furthest thing from her pretty little mind now. "I don't think or care about them. I wouldn't change what I went through. I've learned from it and it's made me stronger."

Before she grew and recovered, though, their words about her weight stung. As a result, Lovato began to starve herself, throwing up anything she actually ate. "I'd make myself sick up to six times a day. My mom was worried, but because I was going through puberty I was having growth spurts, so she assumed that was why I was thinner."

Along with her eating disorder and body image issues came drug use. Lovato was hesitant to go into too much detail for fear of a trigger effect on her young fanbase, but cocaine use was widely reported to be a cause of her breakdown. "It's something I don't really want to talk about," she said. "What I can say is that I was depressed. I would come off stage in front of 18,000 people and suddenly be alone in a hotel room. I'd come crashing down and would try to find a way to recreate that feeling, to stay 'up'."

Lovato says that a lot of the people who paid her to appear also provided her with the illegal substances that would eventually lead to her public breakdown. "Promoters gave me drugs and alcohol in restaurants or clubs. They wanted me to come back so I would be seen there," she said. "They were basically kissing my a--. I thought they were my friends. I thought I was having fun," she added. "Being a celebrity can be dangerous. Nobody says 'no'. That's why so many end up overdosing and dying. It could definitely have happened to me."

The 'Give Your Heart a Break' singer said that once drugs stopped numbing the pain she felt inside, she turned to self-harm to express her frustrations. "It started with my wrists. People saw that, so I cut in places they couldn't see," she admitted. "You do it because you feel so bad inside. You don't know how to take it out other than on yourself."

Lovato's self-destruction came to a head in 2010 when she punched a backup dancer. Shortly thereafter, she entered rehab, which she says wasn't her idea but that she "didn't fight it." While she's grateful for her treatment now, she wasn't thrilled about it while she was there.

"It was really, really hard and scary. I was homesick and lonely and several times I thought f--- it, I'm leaving," she confessed. "But my mom told me I would regret it. This was my only chance." Lovato's days consisted of about 14 hours of therapy, listening to music and knitting. While she appreciates her second chance, she admits, "When I finally left, it was like being let out of prison."

One thing Lovato was happy to leave, at least for a while, was the front of a camera. "I need to be secure in my body before I go back in front of the camera," she said. "Anyone in recovery from an eating disorder would find that triggering, and I'm not ready."