Have you got nerve damage in your feet?
You should be able to feel cramps.
It’s “peripheral neuropathy,” associated with CFIDS. If I’m in a bad enough relapse, I also lose feeling in my index fingers, middle fingers and thumbs. That, however, comes and goes.
Needless to say, I normally try to protect my feet with sox or Birks or shoes. But in the middle of the night?...