I had unprotected sex for the first time dec 8th, it was very brief because it hurt and then we stopped because my hymen broke and was bleeding all over the place, I took plan b the 9th at night. Didn't have any side effects and my expected period was for Dec 20th because my last period started on the 20th of nov and lasts a couple days with heavy flow the first 2 days, and it came on the dec 19th, very heavy flow with some thick clots and had very bad cramps. It is now the 21st and not bleeding at all. Help?