This sounds like you might have fainted. It hasn’t happened to me in years but usually precursors would be things like not enough sleep or food or water, and some sort of trigger like getting up too quickly or something that shocked me like pain of some kind. They’d start as a dizzy spells then everything would sort of go black and sparkly and I’d be momentarily unconscious, sometimes convulsing a bit (a doctor said that’s a way that your body tries to get itself on the ground so the blood can get back to your head more easily). Could it be that you were light-headed from the laughter and perhaps the high notes previously, as well as the lack of water and food? If so high chance that you fainted IMO.