Hi bathsheba, I think I'd have to agree that your's is most likely PP hyperthyroidism. graves is usually diagnosed when there are thyroid tissue antibodies in your bloods (as well as having the suppressed TSH and high amounts of T3 & T4). The fact that yours has responded soo quickly means it's probably either PP or you are lucky enough to be one of the 20% of graves suffers whose meds put the disease into remission within a year. The rest of us usually need RAI or thyroid surgery to try and fix the problem.