Sorry you're going through this. You're not alone for what that's worth.

What helps me is to think a bit about those things that are my go-to wrt trying to feel better. For me it can be change of scenery (sometimes I need this just to remember my go-tos), painting, spending time with some select people, reading a particular book I'm fond of wrt the treatment of depression, etc. And then I try to pre-plan as many of these into my days as time will allow.