Sometimes random with me. I have slept good the last two weeks or so with no issue. Then tonight it is just evading me. No real reason why I should not be able to, but here we are.
Also, this sometimes lasts a day or two or three in a row. I know others have it much worse than me but it still annoying.
At least this time I am not alone. My daughter is up finishing a paper that is due tomorrow.