Hi, on the 25 of this month I will be going to the doctor to get my blood checked for my thyroid. This was a referral from the eye doctor because Of my vision which is fine now. But here's my question... How do I know if I have low thyroid or hyperthyroidism? What do the symptoms cause? I wanna know what it can make you feel in every way. What can doctors do if you do have low thyroid? Thank you. Please answer speedily.