Pete Davidson's Mom Called Him With Heartbreaking Message During Rehab

Pete Davidson says a gut-wrenching call from his mother helped him commit to getting sober ... 'cause he was heartbroken after hearing his mother say she worried she'd have to live through his death.

The comedian and actor dove into the difficult conversation on Theo Von's 'This Past Weekend' podcast ... telling the host his mom, Amy Waters, got real with him while he was in rehab.

Davidson says Amy -- who he calls "the most supportive person in the world" -- told him she was terrified of turning on the TV one day and learning her son died because of his addictions.

Pete said, "That killed me, so I was like, ‘Alright, can’t die until she’s dead.’”

Of course, Pete also thought about his father, Scott -- a New York City firefighter who died on 9/11 -- and he said he couldn't force his mom to go through this sort of heartbreak again.

He added he'd basically need to be sociopathic not to at least try to get sober ... especially since everyone he knows and loves has stood by him while he's aggressively tried to push them away in recent years.

Davidson also referenced his partner, Elsie Hewitt -- with whom he is expecting his first child ... admitting he couldn't be a soon-to-be father if he wasn't clean and sober.