headswim
(noun) a subdued thrumming in the head that is more unsettling than uncomfortable, and does not hurt so much as just feels strange, not at the level of a headache, something lighter, usually induced by substance abuse or an almost-hangover therefrom, but potentially resulting from anything, or nothing, for all you know.
Jake attributed his headswim the next morning to the brand of the whiskey rather than the amount.
"Are you hungover?"
"No, just kind of a headswim. I need an UpTime."
"Are you hungover?"
"No, just kind of a headswim. I need an UpTime."