Miscarry?????

I’m freaking out. I had sex with my boyfriend and he came in me twice over the course of like two days. I am having cramps badly all day today and I’m bleeding but it looks like leftover blood as if I had just finished my period. My period this month already happened (6th - 11th) and I’m in my fertile period. Once when he came I was at the very end of my cycle, just leftover blood. I took Plan B after that. I shouldn’t be bleeding, and I shouldn’t be in this much pain a week after my period ended. Am I just freaking out because of my other friends who have recently miscarried? HELP!