The list of possible reasons is long and not all can be tested: long Covid, ME/CFS, diabetes, sleep apnea, depression, vitamin deficiencies.
I've tried to practice more sports, stopped all coffee and alcohol for a month, slept for longer, nothing changed, but I should continue some of this anyway.
There's also this documentary on long covid or me/cfs where some people have it so much worse, can't get out of bed like the Youtuber PhysicsGirl... Devastating.
Early studies seem to indicate permanent brain damage because of viruses like Covid, so there might be no chance of recovery, just learning to live with it.
Largely I eat leafs and meats while keeping carbs down, keeping dairy low etc. It's not easy to make this adjustment but for me, where I was at physically I would try anything. Going to bed before the kids is for the birds.
My primary doc gave me the same rigamoure that you got so I finally kicked them to the curb and started a search for a new one. Found a doc who suggested the diet change and its worked well, I'll be working on adding some foods back in this year.
I had tried to do it at first but it was not easy to go from 100% carbs and dairy to 0% so I went back, but I'll have to commit to it.
Thanks, it seems a lot of people have similar symptoms, hope some of the causes get better treatments, but also more recognition, feels awful going to work every day like this, and doctors not prescribing time off work because symptoms are to broad/vague and no life threatening illness is found. If I didn't have a family to provide for, I'd just stop working right now.