Is TSH the only thyroid related blood test you're getting? Have you ever had Free T4 and Free T3 tested? Those are the actual thyroid hormones and give a much better picture of what's going on than TSH, since that's a pituitary hormone, not a thyroid hormone, though that's what most doctors test for.
If you've had Free T4 and Free T3 tested, please post those results. Be sure to post the reference ranges, as those vary from lab to lab and have to come from your own report(s). If you haven't had those tested, please talk to your doctor and ask her/him to test them.
You may need an increase in your medication dosage.
If your doctor thinks that TSH is the only test you need, then you need another doctor. As Barb said, you need to be tested for the actual thyroid hormones, Free T4 and Free T3, every time you go in for tests. TSH is a pituitary hormone that is useful in diagnosis only when it is at extreme levels. The purpose of treatment is to eliminate hypo symptoms, not just get TSH within range. When taking thyroid med adequate to relieve hypo symptoms TSH is typically low or suppressed, Free T4 is around mid-range, and Free T3 in the upper third of its range, ora s needed to relieve symptoms.
In addition, hypo patients are frequently deficient in Vitamin D, B12 and ferritin, so you need to get those tested and then supplement as needed to optimize. D should be at least 50 ng/mL, B12 in the upper end of its range, and ferritin should be at least 100.
A good thyroid doctor will do all these tests, as well as an initial test for at least cortisol, and then prescribe medication as needed to relieve hypo symptoms, without being influenced by resultant TSH levels. Symptom relief should be all important, not just test results. If you want to confirm what I have said, click on my name and then scroll down to my Journal and read at least the one page Overview of a paper on Diagnosis and Treatment of Hypothyroidism: A Patient's Perspective. You could even consider giving a copy to our doctor to try and get him to read and reconsider his standard of care for hypothyroid patients. If your doctor is unwilling to diagnose and treat clinically, as described, then you will need to find one that will do so.