I aint had it happen for a while. But i really used to worry about it. The feeling i used get was unreal, it felt like i was fighting for my life. As i said i could feel it coming on as i was drifting off. Whether it had owt to do with how much i used drink as ive cut down now. It made me feel a whole lot better when my mate( i'd never spoke about it) came out that he had been having the experience.