My last period was December 4th or the second, I had unprotected sex on 18th, he did not cum inside me but depending on the guy, pre-cum can get you pregnant too, I started freaking out, So I took Plan B the next day. Now it's January 7th and I still haven't gotten my period. I don't Usually keep track of my cycle so I'm not sure it is consistent. I'm starting to breakout, and having these weird feelings in my stomach, not sure if is because I'm going to start my period or because I'm pregnant. Me and my boyfriend are freaking out worrying that I could be pregnant. Is this a common side effect of Plan B, or should I be seriously worried?