I was supposed to get my period on Feb. 11th, my periods are usually irregular so my period still hadn't started by the 14th. I had unprotected sex on Feb 14th and the next morning (Feb. 15th) I took a blan B one step pill. When should I be expecting my period if techinically it was already 3 days late the day I had sex? Meaning that I am now technically 6 days late. But I have heard that plan B messes with your cycle. When should I start worrying? Please help.