Normal?

So I had sex yesterday it was kind of rough with a condom , I took a plan b like last week and I got off my period a while ago , today I see I’m bleeding from my vagina what could this be ? I’ve been cramping a lot and I’ve had unprotected sex a few weeks ago could this have anything to do with it , or is it just left over period? I know it’s not implantation bleeding because it’s dark red