What Causes Vaginal Cramping And Delayed Period After Having Sex?

I lost my virginity 6 days ago and I ve been having cramps and extra discharge, I m supposed to get me period now or in 3 days or so. The extra discharge I had was clear and runny, but now it s thick and pure white. We did not use a condom and I m not in birth control but he only put it in once. What does all of this mean, what s glimg on with my body?