Sounds to me like you need something to get excited about again.
Surely there is something out there that really lights your fire…the trick is to find that something.
I’ve only gone through one real down period in my life. What worked for me was eliminating the negatives in my life, and seeking out positive things to replace them. It worked. It took time, but it worked.
I did so much slashing from and adding to my life in that period, I scared the s**t out of my wife.
Others have pointed out physical things you may want to check out, in case that’s what’s causing your current predicament.
Or maybe, as others have also pointed out, you just need to relax and enjoy what you’ve got.
Life is too short to be caught up in a funk. Good luck and hope you pull out soon.