i take it every 12 hrs. i am still on yaz. my period is late. i last had sex 2 months ago and my period had been frequent up until now. it should have started the 3rd but didn't. and the on the 4th, there was light bleeding. not today being the 5th, nothing. i haven't felt nauseous. a bit restless at night though sleepy. and a bit of constipation. is it possible this drug is somehow hampering my period?