I have been stable on the same dose of levoxyl... Then out of the blue my tsh showed me as hyper. My doctor told me she was going to have the lab check the free T4.
First of all, the TSH cannot determine if a person is hyper. Only the free T4 and free T3 tests can do that... So, she should have been monitoring those all along. Many, many - if not most - patients in treatment have TSH well below 1.0, and as long as their free hormones aren't excessive, they aren't hyper.
Your current symptoms are ones that can go along either with hyper or hypo. Your free T4 is said to be "normal"... Post that number and lab range if you have it, so we can see if that's true. You must also have your free T3 measured. It could be above range, and if it is, that would make you hyper even if FT4 is normal.
At this point, antibody testing is probably moot. I agree with your doctor. After so many years of proven hypoT, your treatment will still be the same, with or without antibodies. For people who are having trouble getting a diagnosis, the antibody tests are often abnormal before the hormone levels are, proving that treatment is needed.