menstruation irregularities

hi. i was recently diagnosed with papillary c and had the surgery but have not yet had the radioiodine scan and treatment. i have been having menstrual irregularities since the surgery that are VERY different from pre-surgery. my synthroid dose was changed a few times since surgery as we try to get the tsh down to 0. i have been told that the latter could affect my cycle but nothing about how that works or how often people report that, etc. i am 38 and a des daughter. since this cancer shocked the heck out of my life, i find myself so paranoid now that something else is going on, too. of course i know stress affects the cycle too, but believe me, i have had stress before and nothing like this has ever occurred. has anyone else had markedly heavier flow, bleeding every 14 days, etc. following synthroid dose changes? if so, what do you know about it? thanks for any feedback!