You may need some creativity in your life op.
Grow, sew, knit, draw, paint, bake, write, something?
Or learn something new? Oil painting? An instrument?
Build a niche collection or breed an animal which leads you to new places, experiences and people?
Join a choir?
Too low in energy to try? Check out your sleep, diet and exercise regime and check with gp if you have low ferritin, vitamin D, B12, and that your thyroid is functioning ok.
If all ok physically, it helps to fake it until you make it. Go through the motions without thinking too deeply about why. Build yourself a little scaffolding in the form of a routine with rewards at the end of each day.
Journaling is good too! Every evening write down one thing we are grateful for, one thing that went well that day, and a small realistic goal for the next day.
Also, I think it is a very normal and rational response to feel low when you have less ahead of you than has already gone. A certain acceptance or rationality descends and we have to accept that we are in fact not the person who became an Olympic athlete or climbed Everest. We are just fairly ordinary. I am speaking generally of course op, we are all unique in our own way!
You may be depressed and need ADs but depression often comes when you have outgrown the life you are living so in fact this period of heaviness may turn out to be a sort of “pupation period” which precipitates a radical change, and we often have to wade through the deep mud to get to the higher pleasant land again.
Good luck 💐