Green Day have lined up replacement dates for the tour they canceled on the heels of frontman Billie Joe Armstrong's stint to rehab. Right before the rock band heads out on March 10, Armstrong has opened up about his substance abuse problems, and what he went through for treating alcohol and prescription drug abuse.

The singer and guitarist described his rehabilition in "gruesome" terms to Rolling Stone in a new cover article. “That was gruesome, laying on the bathroom floor and just feeling like… I didn’t realize how much of that stuff affected me.”

He further revealed it was his manager who insisted he clean up, after his meltdown at iHeartRadio festival in September.

"I remember tiny things," Armstrong says of the Las Vegas show. "The next morning, I woke up. I asked [my wife] Adrienne, 'How bad was it?' She said, 'It's bad.' I called my manager. He said, 'You're getting on a plane, going back to Oakland and going into rehab immediately.'"

Armstrong said that he'd become a blackout drinker in addition to mixing his meds for anxiety and sleeplessness. “I started combining them to a point where I didn’t know what I was taking during the day and what I was taking at night. It was just this routine. My backpack sounded like a giant baby rattle.”

As previously reported, Green Day is playing at SXSW and a handful of other small venues before heading out on a make-up arena tour. They are supporting their "Uno!" "Dos! "Tre!" albums in addition to two films at SXSW, "Cuatro!" and "Broadway Idiot."