Hello everyone, I've recently been told I have an underactive thyroid. I've been on 50mg of levothyroxine. I had no suspicion I had an underactive thyroid despite a strong family link, by blood samples were actually taken for other gastro concerns. I am feeling worse than ever; exhausted and breathless. GP not helpful. I have my blood results and was wondering whether anyone could offer any wisdom or insight as it would be appreciated! My GP left me out a prescription for thyroxine and that's been it. I'm a 28 year old female.