Yes, I know what you mean about the racing heart, shortness of breath, anxiety, palpitations etc!! I had an underactive throid for 17 years previously and then for some reason the thyroid has come back to life and started overworking. I am on beta blockers, Neomercazol and levythroxine at the moment and shall have to take it for a least 12 months to try and force it back to underactive. The weight gain with Neomercazole is awful but it has stopped the other symptoms.

thanks for your reply.