so either I'm dumb or it's only obvious now, but right click is definitely doing both left and right click regardless of what i'm doing. i switched USB ports so it's either a driver problem (though i updated them) or a hardware problem.
i will have to find another mouse to try tho.
edit: ok so i took the mouse apart once i figured out how to find the screws and i cleaned out a little bit of cat hair and now it's fine. i really don't know how that caused that, because it didn't seem like it would cause pressing the one button to trigger another button, but what do i know.
now all i gotta do is figure out what's the deal with my GPU, and I already cleaned out the cat hair.