Demi Lovato has been very vocal and open about her stint in rehab for substance abuse, self-harm, eating and bipolar disorders -- and she's also been a role model to girls going through similar issues. The 'Heart Attack' singer is determined to let those suffering know they're not alone, because that's exactly how she felt once she was there.

The 'X Factor' judge admitted that once she got out of rehab, she realized who her real friends were ... and there weren't as many of them as she thought.

"A couple of months before I went to rehab, I had a birthday party, and there were a couple of hundred people there," Lovato told Company magazine (quotes via Entertainment Tonight). "When I turned my phone on after being in rehab for three months, I expected lots of text messages and phone calls," she said. But what really happened? "I had four texts. That was a wake-up call."

Ouch!

Lovato continued, "I don't have loads of friends. I used to, but then I realized, do any of them actually care? Now I have people who, if I break my leg in the middle of the night, will come to the hospital with me. Or they'll answer the phone at 4AM if I need them." Good, Demz! You deserve it!

As for gossip? Lovato stays out of it, but she does toss some slight shade toward Taylor Swift, of whom she's never really been a fan. "I don't care about Taylor Swift's love life. I don't care about Harry Styles' love life," Lovato griped about the romantic tabloid drama in Hollywood. "I care about mine. I find it weird that people are so obsessed with other people's love lives!"

As for her own love life? Lovato doesn't talk about it, but she did insist that it doesn't involve Niall Horan. Bummer!

Watch the Demi Lovato 'Heart Attack' Video

More From PopCrush