Desperado, I felt the same way many, many times over and over again. The one thing that's for sure is that if I wait long enough, I feel better. I suppose that's not much help but I hope it's something. I have health problems also. Even with old age and health problems I still come back to a place where I'm okay with being alive and hopeful - a bit - for the future. And that's enough.
I hope you start feeling better soon.

Hang in there, try to distract yourself with things you like all day long.