Aw, sorry to hear you're getting crook again
Maybe you have a more abundant supply than me... But I never get engorged anymore, even when I go to work and forget to express at lunchtime! (Well, that's not true, I will get engorged if I haven't fed her for 10 hours which has only happened probably twice in her entire lifetime, LOL!)
I would pump or hand-express from the sore side - whatever's more comfortable. I find my boobs are pretty savvy at adjusting supply these days so even if we've skipped a couple of feeds it only takes a day of frequent feeds to pick back up again. But my RHS is kaput now. After a couple of days of no feeds I tried her again on that side when I wanted to give my leftie a break (we'd had bad attachment or something but it was feeling a bit sore) and she gave a few sucks and then looked at me blankly.
I am very lopsided though.
I really hope you are feeling better soon.