The singer also opened up about the progress she's made in dealing with her substance abuse issues since last appearing on CBS Sunday Morning in 2016.
"I was probably 24 when we did the interview, Lovato says. "I'm in recovery for a bunch of things and I had been sober for how many years, but I'm still miserable. For the first time in my life, I had to essentially die to wake up."
Lovato's CBS Sunday Morning interview -- which airs March 21 at 9 a.m. ET -- arrives ahead of the singer's four-part documentary series, Demi Lovato: Dancing With the Devil, premiering March 23 on YouTube.
The tell-all docuseries explores Lovato's devastating overdose, which left her with three strokes and a heart attack, as well as blind spots in her vision that block her from driving.
"I didn't control any of my life at that period of time," Lovato tells CBS Sunday Morning. "But, yes, I also needed to grow up and take control. And that's something I haven't done until the past two years of my life, which is [why] I'm now in control of my finances. I'm now in control of … the food that I eat, how often I work out."
In addition to her upcoming YouTube docuseries, Lovato is also releasing a companion album, Dancing With the Devil… The Art of Starting Over, on April 2. She announced that her new single "Dancing With The Devil" will arrive on March 26.