I took synthroid for over thirty years, monitored by an internists, our family doctor. I began having episodes of anxiety and panic attacks, then periods of depression. Each would last for a month or so and go away, but return later. About six years ago, it began it all over again, but this time I couldn’t function. Tests revealed nothing and the doctor said it was emotional. I saw a psychiatrist who after several sessions and thyroid discussion, told me to see a endocrinologist immediately. I did, I was diagnosed with hashitoxicosis, which is an autoimmune disease where my thyroid swings from high to low levels of hormone. When my thyroid was producing hormone, that along with the synthroid ws like an overdose to my entire system. He took me off synthroid and I haven’t had a panic attack since. I can tell you, synthroid and a bad thyroid CAN cause severe metabolism issues that act as emotional disorders. My endo guy calls the thyroid “the second brain”.
That is a very, very rare condition that you have, but it causes Synthroid to be at periodic overdose levels because of the swing of levels in your system. Overdose of any thyroid replacement therapy would cause those problems.