Do any of you ever feel like you want, need and HAVE to go to bed, no matter what time of day it is??

I know this sounds bizarre but say you are in the middle of something, anything, day to day and find you have to excuse yourself from the room/person/situation and go home to bed? (if you aren't already home??)
It's a horrible feeling and there is no overcoming it, for me personally, when I feel the urge, if I try to fight it often makes it worse

Obviously at work, this in unavoidable, but, most of my shifts are only 4 hours these days and I find I can 'cope' with that, just. On an 8hr shift though? It's a nightmare!! I often pump myself full of Red Bull or Costa's to try and 'stay with' the land of the living, so to speak

lol!
Does anyone think it's just because I am often over concentrating, concentrating so hard or for too long, that I tire my brain out? Is that a feasible/plausible explanation??
