03/28/2013 at 04:40 PM EDT
Three years after her 18-year-old son Michael committed suicide
, Marie Osmond says she still has moments when she drops to her knees unable to breathe: "You cry until you can't cry, and then you cry some more." But each time this mother of seven other kids (Michael was one of the five adopted by Osmond and her second husband) picks herself up.
Now Osmond, 53, is sharing how she got through her darkest days
in a new book, The Key is Love
, which was largely inspired by her mother Olive's advice. "Some people don't talk about these things, but we do," she tells PEOPLE's Mia McNiece. "I think it's important. I'm healing every day."
About six months before Michael died, during a "Meet 'n Greet" after my Vegas show
, a woman gave me a hug and said, "Oh, Marie. You've been through depression, divorce, kids in rehab . . . What haven't you been through?" I answered, "I haven't lost a child. That would be the worst thing."
On February 26, 2010 the "worst thing" happened. My sweet son left me, his family, and friends by jumping from the balcony of his eighth floor college apartment in Los Angeles. Even as I write this I want to cry out, "Please, don't let this be true."
Exhausted from a non-stop week with shows, I was staying in a hotel room at the Flamingo that night with my daughter Rachael. My cell phone rang around 1:30 a.m. and it was a guard at the gate that leads into my neighborhood. He said, "Someone is here from the coroner's office. They are coming to the Flamingo to see you."
My heart dropped to the floor. I said to Rachael, "It has to be Michael."
"No, Mom, no," she said. "I'll call him." She dialed and redialed. She kept saying, "Pick up, Michael. Be there."
The officer came to the door. He said, "I'm very sorry to inform you that your son Michael committed suicide at 9:25 this evening."
I thought someone had run a knife into my heart.
I adopted Michael a few days after his birth. His birth mother was an unwed teen. Michael was an adventuresome child. It was impossible for anyone in the family to stay upset or angry if he was around. He would come up with hysterical voices and characters. Even as a very little boy, Mike would notice and reach out to those who were marginalized because they were different.