I would suggest an ultrasound, too. All my levels were normal, I knew something was wrong, I later found out that I had cancer. Don't mean to scare you. My only test that was not right was the TPO ab, which meant I had Hashimoto's. I had irregular periods, weight loss, hair loss, swallowing difficulties, hoarseness, blood pressure spikes, fatigue...get an ultrasound to check for nodules...
Have you had any antibody testing done, or an ultra sound? You could have an autoimmune thyroid issue and still have normal levels.
As gimel said, please post whatever results you have, so we can help you better.
Please post whatever thyroid test results and reference ranges you have so that members can provide the best response.