Does Irregular Menstrual Cycle Mean Pregnancy?

Hello, so on the 2nd of April my boyfriend and I had unprotected intercourse. He did not ejaculate or anything he was very precausious, well except for the condom part, but anyways I started my period on exact day that I was supposed to. It was very light though. Which I figured that could be because I had just quit sports and I had changed my eating habits. Then we had intercourse again and I took a Plan B, but I started bleeding yesterday and a little today. Which I shouldnt be starting until the 8th. I guess my question is should I be worried that I am pregnant since my menstral cycle is irregular?