Heather Locklear's private pain was made public when she was rushed to the Los Robles Hospital & Medical Center in Thousand Oaks, Calif. on January 12. (The actress' sister was reportedly scared the '90s TV star had overdosed on a combination of alcohol and prescription pills.)
"Heather has been out of control for many years," a source tells the new issue of Us Weekly (out now). "Her drinking has caused her to fall out of many friendships."
Locklear's problems only worsened when she and beau of four years, Jack Wagner, called off their engagement in November. "She doesn't get out of bed most days," the source explains, adding that "Jack kept her on the straight and narrow, but he couldn't keep Heather sober."
Though Wagner, 52, "begged her to go to rehab," it wasn't until after their breakup that Locklear "entered a treatment program, which her family was able to keep quiet."
Unfortunately, the former Melrose Place actress, 50, "didn't take it seriously" and appeared visibly drunk at an L.A. Lakers game January 10.
For more on Locklear's breakdown -- including how her 14-year-old daughter Ava is coping -- pick up the new issue of Us Weekly, out now.