thanks
@lilygrace I think I'll look into that.
I never fainted before so I'm not totally sure that's what it is.
All I know is, I was scrubbing the floor, then I stood up, looked up (don't know why), glazed off and then without any other warning, started to actually fall asleep while standing, but fortunately had enough alertness to know to hold onto the bathtub and closed my eyes.
Moral of the story: probably drink water, don't work too hard, and it might not be the best idea clean the bathroom at 2 AM)