Wow Cabal, that was some pretty honest sharing. Definitely food for thought. Who knows, you could be giving many of us a glimpse of our future.
I have a couple of simple ideas; maybe they’ll be helpful.
* I think you’re right about exercise. Endorphins and all that. This would also vastly help any sleep issues you may be having (in my experience). Sure, in the big picture what is the overall “value” to the world of you doing exercise? Admittedly not large, but I do think it will help you feel better, maybe think more clearly about things, while going through your days and plotting more meaningful activities.
* Volunteer work? Teaching (of any form)?
* Something intellectually challenging where you can see your progression. Pilot’s License?