@blueveinedthrobber,
Trains. The answer (for me at least as I fast approach 63) is trains. They are what helps restore my youthful optimism and happiness.
Toy trains, real trains, train forums, pens designed like trains, checks with trains (choice of diesel or steam), paintings and sketch drawings of trains, youtube videos of trains, sounds of trains.
Sorry you're in this rut; life has been tough and rough on you at times and it takes its toll but you still have a chance to turn it around. Find what in life makes you happy and essentially overdose on that, be it music or art or something else. Once happy the optimism can start seeping back into your system.
Wishing you the best on this, sorry I can't offer you better.