Plan B to early period


Okay so long story shirt I had protected sex but then he came and he took the condom off since we were done.. but I sat on top of him and his penis just slipped right back in and and we went for like two strokes then realized there was no condom and he was still coming. So we rushed to store and got a plan B but ever since I’ve been bleeding. At first it was just a little so I thought okay maybe he just popped my cherry but it’s gotten really heavy and I’m having cramps. Idk if this is normal buy I pretty sure it’s not. And I wasn’t supposed to start my period for another week btw. Can someone please tell me what’s going on