Hi Martin! Sorry to hear of your troubles.

I have a similar story. Trained in martial arts, off and on health permitting for most of my life. Finally received my black belt about 10 years ago. Can not currently attend a dojo due to my TBI-induced symptoms (car accident when I was 18; I'm 54 now). I do try to train on my own when I can, which isn't often.

I have some of your symptoms, others are different. The migraines are the worst. I also suffer from Chronic Fatigue Syndrome, and psychological issues such as nearly uncontrollable rage (the martial arts training is actually helping me to deal with that).

I can say not to necessarily give up on the karate. I had to give up many times, but always managed to trickle back. Then one day I found myself passing my shodan test (on the first try). Hang in there.