I had unprotected sex with my bf on 3rd day of period and my cycle is of 28 days. During period I use to bleed for 4 days with minimum or no bleed on 4th day. After having sex I don't bleed on 4 th day. Kindly suggest is there any chance to get pregnant. Also it is almost 36 hrs after sex so can I take contraceptive pills now will it help me to avoid pregnancy or there is any other precautionary method through which I don't get pregnant. Pls guide as I don't want to get pregnant.