Sorry you are suffering.
Could it be a histamine / mast cell response, seen a few covid people complain of this and it's also common with peri (estrogen and histamine go around in a loop, a few threads going on this currently)?
Also I had a thyroidectomy ten years ago (long story, absolute horror show) and one thing I've learned along the way is NEVER take a GP's 'all normal there' at face value, have you got copies of your results? The level of avoidable suffering going on (particular for women who make up 90% of thyroid patients) is a medical (and feminist) scandal.
How are your periods? Have they tested your iron? Low iron is very common and it's incredibly badly treated and understood in primary care (and also has a link with histamine and mast cells)
https://www.oatext.com/iron-deficiency-without-anemia-common-important-neglected.php - many symptoms are wrongly diagnosed as psych when they are in fact easily fixed with iron supplementation, good list of symptoms in that paper.
Hang in there. As someone who has really, really, really suffered with my health over the last decade, it's important to cling to this truth: Logic dictates there is an answer to your problem. There is. So don't give up hope. However, this is probably going to mean taking control of your own health, this can be tricky and disheartening, but on my darkest days I have clung to the fact that there IS an explanation. 99.9 times out of 100 I have found it. I've had to be a bit creative to get around unhelpful and patronising doctors, but it can be done. Lots of women on this forum doing the same.
Reb
x