I started taking Synthroid about 20 years ago. Have been on every does and have never felt good. I finally got so tired of the panic attacks and irregular heart beats that I stopped taking it. In 30 days my tsh was over 150 and my t3 and t4 were almost none. I went to an endo and all they did is put me right back on the same does immediately saying I was in danger of dying. It's been now 15 days back on it and I'm miserable. The panic attacks are back, skipped beats are all day long, I have a cold I can't get rid of a constant headache and blood pressure spikes... Can anyone tell me any other treatment that works? I'm so done with all of this. It's almost worth stopping if again just to enjoy the good days!!!