Some Dude Says Ambien Made Him Propose To His GF...

We learned from Roseanne last year that Ambien makes you tweet offensive stuff . . . who knew it also made you ROMANTIC?

A guy posted a story on Reddit on Monday about what happened to HIM when he was on Ambien.

He says he couldn't sleep so he popped a LOT of it in the middle of the night and, apparently, he proposed to his girlfriend.

He had a ring because he buys and sells jewelry on Craigslist, and he had no idea he proposed until the next day . . . when he realized he'd also changed his Facebook status to "engaged" and it got more than 150 likes.

He says he hadn't planned on asking his girlfriend to marry him for at least another year and a half and, quote, "probably would've gotten her a better ring, but Ambien sped up the process."

Now he's swearing off it for good.... His full story is below: