So I had unprotected sex and he finished but I believe I was up in time. In the time of 72 hours I took plan b and a couple of days later I had started a period that lasted for 4 days. That was in January,it is now February 6th and I usaully start on the 1st or 2nd. I noticed I have some light brown discharge but I am late for my next expected period! Please help!?