is back with a successful album, even topping former flame Joe Jonas
, but she hasn't forgotten her past mistakes
Lovato, who sought treatment
over a year ago for "emotional and physical issues,” says she employs a new vigilance when allowing people into her inner circle.
"Just to be careful who you trust. Sometimes you don't know who you can and cannot trust," the singer and actress, 19, tells Parade
. "I still learn that over and over again."
Lovato recently shared just who fits that criteria on her personal blog
, writing, "I think about my family and friends and fans who support me
no matter what – it's that unwavering love that helps me stay calm and focused."
Additionally, she credits a better work-life balance for aiding in her recovery.
"I'm in a much happier and healthier place now, so I'll be able to decide when I need time off," Lovato says. "It's a different era in my career."