Monday was the last day i took my birth control pills, so i have missed 4 days. I had unprotected sex on wednesday night, and he did ejactulate inside me. I checked my ovulation schedule and it says wednesday and thursdays are the strongest days. I started my period this morning (friday), its pretty heavy but has lightened up through out the day. Could this only be because of my missed pills or is there a chance i could get pregnant?