Hello. Thank you for coming to JustAnswer with your question, and welcome.
Your doctor is looking for the cause of your thyroid disease. There are different types of disorders that can affect your thyroid gland. For instance, a couple disorders are called Hashimoto's disease, and Graves disease. Both of these are autoimmune disorders (meaning your immune system is causing the problem). Your test results suggest that one of these disorders may be your problem, but you will have to talk to your doctor about that.
Here are some links for more information about those disorders: