Re: TSH reflex to FT4 Question
Now that you've posted symptoms, my guess is that you may be leaning toward hypERthyroid. Those are typical and classic symptoms of Graves' disease. Your TSH isn't yet low enough for full-blown Graves', but it could be headed that way.
You must insist on more tests, specifically a second TSH, free T4, free T3 (because it may be excessive even when FT4 is not yet), and TSI antibodies (specific to Graves' disease).
TSH alone is never enough to explain multiple thyroid-type symptoms. If your MD won't agree to the additional tests, please find a better MD.
"We can complain because rose bushes have thorns, or rejoice because thorn bushes have roses." Abraham Lincoln