Don't despair!
Check if you have EBV (epstein-barr virus residues or active) in your blood. Then read Anthony William's book about thyroid. It will open your eyes to new facts.
You can heal. Trust your body it is fighting the EBV which now is in your thyroid, probably liver etc. In some people it triggers hypothyroid, in some hyper, and in some switching between with "autoimmune" inflammation. The doctors dont link EBV to these issues because EBV is not active in the blood anymore. But it is settled in organs, waiting for a trigger such as lot of stress, and eating on toxins and your body, causing all sorts of issues including anxiety.
You can heal. I'm sure of it.
I got this advice and book from someone who healed her thyroid.