Goodness, I can relate. I get bad anxiety and panic when my stomach is off, which seems to be a lot anymore.
My tsh has been normal, but my ft4 is LOW at .5, and my ft3 is 3.5 which is normal. I don't get it, and my anxiety has been horrible! I just don't know what to make of it.
Panic and anxiety is the worst.
You're talking about your TSH level being in range all these years, but you haven't mentioned Free T3 and Free T4... have you ever had those tested? Those are the actual thyroid hormones and correlate with symptoms, while TSH is a pituitary hormone and does not correlate with symptoms, nor does it correlate with the actual amounts of thyroid hormones in your blood.
It sounds like you're symptoms are actually caused by inadequate thyroid hormone levels. Even though your TSH is "in range", that doesn't mean your thyroid hormone levels are adequate.
Depression, anxiety, panic attacks, brain fog, stomach issues, muscle/joint issues, etc can all be present with hypothyroidism.
What vitamin levels did you have tested? The main ones we recommend having tested when one is hypo are vitamin D, ferritin and Vitamin B-12. Vitamin D and iron are necessary for the metabolism of thyroid hormones and vitamin B-12 deficiency comes with its own set of problems shares some symptoms with hypo, such as fatigue and brain fog.
Have you ever been been tested for Hashimoto's? If not, you should be. Hashimoto's continually destroys thyroid tissue until there's no healthy tissue left, and if med dosage doesn't keep up the destruction, symptoms are not alleviated.
If you have test results for Free T3 and Free T4, please post them, along with reference ranges, which vary lab to lab and have to come from your own lab reports. If you haven't been tested for those, that would be the first order of business.
Also, please post whatever vitamin levels you have, with reference ranges, as those also vary lab to lab. We can go from there.