How do I stop treating every task as being equally urgent?

I'm having a lot of trouble prioritizing even basic things. It gets overwhelming when everything feels like it needs to be addressed immediately. I can't be in two places at once, but I feel like I have to be in order to keep on top of everything, and the stress from the overwhelming pressure to do everything at once keeps burning me out and I do nothing for hours instead. I just end up feeling guilty and getting angry at myself about it, which does absolutely nothing to help my motivation.

I know from an objective view, I could do thing x first, then thing y, and then thing z in order of importance, but my subjective impulses keep saying "DO IT ALL RIGHT NOW OR YOU'LL BE SORRY!" and I exhaust myself, give up, and feel sorry anyway.

To anyone else who has this problem and found a way around it, would you mind sharing?