I regret publishing a sloppy conference paper
There is one very easy answer to your problem.

Relax. Do nothing. It's fine.

Really. Your data is good, your results are interesting, people are reading your work, and you haven't found anything particularly wrong with your science. This is more than most of us can say about our first forays into publishing.

That being said, maybe you should work on how much you let small problems get to you if you want to survive in academia. If grammar errors and awkward formulations in a published paper already make you be unable to sleep, I worry that the real setbacks that characterise academic work (experiments that are not working out, unjustly rejected papers, dozens and dozens of faculty applications that you never hear back on, ...) will do to you.