My thyroid was damaged by radiation and chemo for neck cancer back in 2013.
ive been on synthroid for a while.
see your Dr often. Get blood work often. Dial in the script. It takes time. My primary consults with an endocrinologist why my numbers get weird just so she doesn’t have to “trial and error” the dosages too much.
Good luck.
Stay aware, and try to stay active even when you don’t feel like it.