Yep, a few times it happened way back when i first started vaporizing. Those times I would put an enourmous amount of THC into my blood and then when things got to shakey and twisted I would realize I needed to lie down and try to go to sleep.

I'd get to thinking, get to focusing and I remember about 3 specific times where I'd jump or sit up real fast and have to think for a few seconds why I felt strange, and I'd realize I was just distracting myself too much and I had either messed up my breathing cycle or somehow "forgotten to breathe". It was indeed hilarious the next day but I was frightened at the time.