Im 16 and was just diagnosed from a blood test with an under active thyroid. I was diagnosed a few months ago and now take levothyroxyn everyday whic seemed to only improve how tired i was. I also take celexa (3 week taking it) everyday also for depression and anxiety an i have chronic migraine/tension headaches (since I was in 3rd grade). Everyday I feel horrible, fatigued, nauseas, weak, anxious, sad, my skin looks horrible and I bruise so easily, irritable, achy, short term memory loss, I just don't want to do anything anymore. What all can a low thyroid do to your body and what is a normal thyroid supposed to do.