Last week, on Monday, I had unprotected sex. He did not come inside of me and then I started my period on Tuesday. (My period only lasts around 4 days). So I thought my period was done on Friday, and we had unprotected shower sex. Once again, he did not come inside of me. When I got out and wiped myself, there was some blood. But then my period was over with. I took the Rite-Aid version of "Plan B" on Sunday. Now I am experiencing bleeding as if it is my period and having back pain. is it normal ? How bad will it effect my body?? My period is supposed to come August 16. Will it still come where I am bleeding now?? NEED HELP PLEASE