Hi Potential,
well, today is actually one of those days for me, so here's my fallback option. I don't participate in society today. I don't work a fulltime job at the moment and today is one of my off days. Did some paperwork this morning, mailed it in, and that's it.
Tidied up my living room, took a shower, read a book for an hour, prepared a semi-healthy meal with meaningful, good vibrations-music on (for me at least)... Today, there's nothing more i'll do in a 'productive' sense.
When I switch my internet off in ten minutes, I'll read in another book and lie on my couch and drink a lot of tea.
At noon or evening, I'll go on a ride in nature with my mountainbike and listen to a clever or entertaining podcast, fully aware and maybe thankful for not participating in society today. As was said before/above, movement, sports and physical exercise do help easing grimdark moods and days. The hard part is dragging yourself to start.
Hope you feel better soon.