They had told me, "your tests are within normal range", for years. My endocrinologist and others that I read books written by them, said that doesn't always matter, some may need a small dose of thyroid meds. to help set things right.
It's always good to be tested every 3 yrs, and if on thyroid meds, every 6 months to 1yr, is recommended.
I'm not saying it's always thyroid issues, but they sure can cause havoc, even being DXed incorrectly with mental disorder(s). It was just a physician's assistant that felt the nodular feeling, that the other docs seemed to fail to feel, I'm happy my GP was out that day, otherwise I'd still be more ill than I am. Feeling crappy still but a little improvment.
Hyperthyroidism can fuel feelings of anxiety, insomnia,hypersexuality, racing heart, some pdocs can mistake for bipolar.
Hypothyroidism has many symptoms of depression, so again it goes unnoticed and they hand out antidepressants,etc.
Several years I suffered,several years being looked upon as a "hypochondriac" I am sure, then I progressively get worse physically, all the stuff that signals Hashimoto's.
It can never hurt to look into other factors, if one can, to help prevent years wasted being wrongly DXed and medicated.
Lots of luck to you.