I just wanted to add, without having read the full thread in depth, that your symptoms sound more like those of the respiratory virus I am currently fighting, than they do like my father’s and sister’s hypothyroid symptoms.
Also, as far as migraines are concerned, I find that keeping my salt intake up is the best defence.  Migraine auras are one of my indicators that I am not getting enough salt.  Fortunately, if an aura starts to develop, I can almost always head it off by eating a small handful of salt (probably about 5 grams’ worth, more or less).  That saves me from having to go lie down for a minimum of two or three hours.
I am very fortunate that on keto my auras never (at least so far) seem to develop into full-blown migraines, because if things get to that point, the only effective treatment is a couple of days’ bed rest.