Demi Lovato has never shied away from talking about addiction and eating disorders, both of which she battled as a teen pop star before entering rehab. Now, the "Confident" singer has opened up in-depth in a new interview in American Way magazine.

The 23-year-old pop star and mental health advocate spoke about her path from beauty pageants to television stardom and the body image issues that plagued her along the way, eventually leading the singer to alcohol and drug abuse.

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"I lived fast and I was going to die young," she told the magazine. "I didn’t think I would make it to 21."

In rehab, Lovato was diagnosed with bulimia and bipolar disorder. She said she was determined not to be a child star stereotype, but it wasn't an easy road and she relied more and more on drugs and alcohol. "I thought, 'I'm not in treatment for a drug and alcohol problem,'" the singer said. "But once I started eating again, the other issues got worse. It was like whack-a-mole."

In the years since, Lovato has credited her ex-boyfriend, Wilmer Valderrama, with helping her stay sober and maintain her recovery. The couple's six-year relationship ended earlier this month and they announced the split in a joint post to Instagram.

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Longtime Lovato friend and fellow performer Nick Jonas spoke to ET recently about the breakup, saying he thought the pair's upcoming tour was "probably the best timing for everyone."

Meanwhile, the "Cool for the Summer" singer has been having an on-again, off-again relationship with social media, taking aim on Twitter at -- among other things -- tabloids and celebrity culture. Check out what she's had to say in the video below.