Hi. Did I understand correctly that you have been treated and your FT4 went absolutely nowhere? I would definitely ask an endo why your TSH is so "low" along with your low FT4. How would they recommend proceeding because further treatment may just lower your TSH? I hope you are able to find a good doctor that will listen to you and your symptoms. If so, maybe the secondary hypo (any pituitary connection) can be pursued.
Good luck-unfortunately in my case this has been a 14 year journey with no real answer. I too was complaining for 6 years!! Try to stay positive- can be difficult at times. My last labs were TSH 2.49 and Ft4 1.8 (H)-still feeling bad.
You should also have your DHEA, cortisol, B12 and Vit D checked, too. It is a good idea to know everything that is going on.
Thanks! I am going in 2 days to have lab work done and I am requesting a FreeT3 along with the other tests.
Levels might relate to Adrenal Fatigue, other non-thyroid problems such as allergies, hormonal imbalance, yeast, etc. Depending on your FT-3 in which you did not list for whatever reason, might suggest hypothyroidism due to low pituitary function. An Endo. might be a good idea.