@lewin I'm sorry to hear that you still haven't found any answers from your doctors and are having trouble getting another appointment. You also started an earlier discussion on Polyneuropathy here - https://connect.mayoclinic.org/discussion/polyneuropathy-2/. I'm not sure if you have been diagnosed with Polyneuropathy or Autonomic Neuropathy or if you have seen a neurologist. If it were me, I think I would try to seek help at a teaching hospital or major health facility like Mayo Clinic or Cleveland Clinic. Here's a search function for finding a neurologist at Cleveland Clinic that shows their rating and some patient comments:
https://my.clevelandclinic.org/departments/neurological/staff?q=autonomic%20neuropathy&dFR%5BsearchCollections%5D%5B0%5D=113