Can Running Make Your Period Irregular Pregnant Or Just A Messed Up Cycle?

Pregnant or just a messed up cycle? - can running make your period irregular

A month ago, my friend and I had sex and that I was the first time. Just a day before it happened I stopped after a period of 2 1 / 2 runs per week. My time has always been illegal. I arrived last week, but not yet arrived. We used a condom, but not in the pill, because I am only 2 weeks. I have not got my period, but a few days ago I had severe pain and went into the bathroom and there was blood, which has a little excited. I have a stamp and the next time I went into the bathroom, I took the pad and there was no blood. This happened again one days later, then a day later. I get cramps very bad time, but no blood. I am a little concerned that you may be pregnant, but I heard sexfirst period to clean up. Help me? I'm really nervous because I'm only 18