I've needed glasses for a while now, but when I actually have them they don't make a noticeable difference to my vision (they oddly still make the DMV happier though)
We've been in the middle of a heat wave here for a little over a week, so that might answer that as fa as hydration is concerned. This seems the most likely, as it's the first time i can recall ever having a headache so bad and so suddenly. Was like getting cracked in the side of the head with a golf club.
Stress at work combined with depression has kinda had my back and neck tight. Also a prime suspect for the problems as this month at work has absolutely sucked balls.