demi-lovato-230-2.jpgDemi Lovato covers the February issue of Seventeen Magazine, and the 19-year-old starlet chats about her struggle with depression and how she's improved her life, but she also dishes on her occasional drama with fellow Disney darling Miley Cyrus.

On her dark period, Demi tells the mag, Im not gonna lie. I was self-medicating. I was doing things like drinking and using [drugs], like a lot of teens do to numb their pain. However after a stint in rehab in late 2010, she's doing much better these days. I dont drink, I dont do drugs, I dont throw up after my meals, I dont starve myself," she says. "Theres nothing that I do that I feel ashamed of.

While her relationship with Miley isn't always perfect, she knew she could count on her when things got tough. "No matter how many times we fight, we will always be in each others' lives," she tells the mag. "Miley and I are very strong-headed, so when we fight, it's brutal and we're like, 'We're never going to be friends again!' Then two days later, we're like, 'I love you and I miss you!'" So how's her friendship with Selena Gomez? "Selena and I, we never fight," Demi says. "Shes not a confrontational person at all. Both of them will never leave my life no matter what happens, because weve been through so much together.

Demi is proud of her sobriety, and she says she feels "more confident, happy and healthy" than ever before. "I have so much to look forward to -- from little everyday things, like where I'm going to go shopping with my friends, to big things, like heading out on the road [on tour], or even really long-term things, like what my next big project will be."