period

I KNOW MY PERIOD ! My period was being odd this month, as crazy as that sound. But I've always been a heavy flow. However, this month I wasn't heavy at all. I had sex, and used the pull out method. And know for a fact that he nut in me. And this month my period wasn't heavy, basically ended in 2 days and it normally ends in about 3, with mild cramps.So does anyone know why my period is so light this month ? Why it ended a day early ? And why on day 1 my cramps were so bad it made my body weak and like I was gonna vomit ?