Sounds like you need to see your doctor and get some thyroid related tests done. Specifically I suggest tests for Free T4 and Free T3 (not the same as Total T4 and Total T3), TSH (and if above range, then TPO ab and TG ab tests for autoimmune antibodies related to Hashiimoto's Thyroiditis), and an ultrasound test of the thyroid gland. Since hypothyroidism is properly defined as "insufficient T3 effect in tissue throughout the body due to inadequate supply of, or response to, thyroid hormone, I also suggest testing for some important variables that can affect the tissue response to thyroid hormone. Those tests are cortisol, Vitamin D, B12 and ferritin.
If you can get those done, then post results here, along with reference ranges and we will be happy to help interpret and advise further.