I have recently had my thyroxine reduced to 75mcg because of palpitations...I have been feeling a lot better as apparently my dose had been far too high (long story). Over the last few months I have been experiencing horrendous heavy periods...after a night shift last night I woke with palps on exertion, I had a full blood test a while ago showing ferritin low, I started taking iron...am confused as to whether palps to do with periods? doctor read my bloods said I wasn't anaemic. Have booked another appointment with Dr next week. Thank you for any advice. oh I am 49 so no doubt premenopausal!