Im a 26 year old who in the last 4 months was told she has POCS. My been taken note of my period s and they come every 2nd month and usually last 5 days and are heavy and dark in colour. Last week I was put on Clarithromycin for a chest infection and cold that Ive had for 4 weeks now. My period started yesterday and its very light (so much so that I prob wouldnt need to use a tampon ) and red in colour. I have been having unprotected sex and Im fine with this. Could the pills have changed my bleeding? Could I be pregnant even tho I dont have signs ? Thanks for your time :)