Valerie Fairman was desperately trying to get clean for years before she died from a suspected overdose ... according to her mother.
Valerie's mom, Janice Fairman, tells TMZ her daughter checked into 5 different rehab treatment facilities over the last 5 years, but she fell off the wagon every time. She says the last time was just a few months ago ... after Valerie had served time in prison for a probation violation.
Janice tells us she last spoke with Valerie a week and a half ago, and while they didn't discuss her sobriety, Janice says Valerie sounded "way up" and "very good."
As we reported ... Valerie died Wednesday while visiting a friend Pennsylvania. Janice says she does not know the friend.