I had unprotected sex, and the next day used plan b. Then about 2 days later I had unprotected sex again , and I used plan b the very next day. I got my period, it was a few days late, but I'm experiencing cramps, and really light bleeding. The blood is red, a very prominent red, but I'm having pretty bad cramps. And I bleed the most when I am sitting on the toilet. What is this?