I'm no hygienist so I don't know the ratios but if you're not using a/c then I guess there's a large difference in the amount you're losing to perspiration. I'm pretty sure the caffeine in your coffee doesn't help either.
"Pee is clear so well hydrated...."
Right. And, as I suggested, maybe you're over-hydrated.
How long do you leave it between your last drink and going to bed. It should be at least a couple of hours, ideally.