I go to a "black sheep" doctor who treats hypothyroid and adrenal issues more by symptoms than by raw labwork numbers. One of the symptoms on the list (doesn't affect me, but I have a friend who was in your same boat) is extreme lethargy after meals, and/or "goosebumps"/inablility to stay warm for at least an hour after meals. Just tossin' it out there for consideration.
Everyone's mileage varies, but I'm curious if anyone else is also very permissive in their sodium intake and will deliberately try to retain water, at times, in order to feel better? I was actually 'prescribed' salt tablets as a pre-teen and acquired them again this past year when my BP regulation bottomed out again. It's nasty for the scale, but extra salt has always helped me when my numbers have crashed out so badly I'm having trouble functioning.
I dont deliberatly increase salt but I dont restrict salt and during the summer I add salt foods to compensate for sweat.
I have low BP but oddly have had very few negative symptoms from it. Rarely feel dizzy or faint.