Bleeding after anal

Hello! I just want some advice on something that happened last night...so me and my BF have been having anal sex for a couple months now (as well as vaginal sex) and last night we had really great anal it felt amazing. But I noticed afterwords after I was in the bathroom cleaning things up down there that there was some blood. I kept wiping and after a few wipes the blood was gone. I hope up this morning and wiped to check and there was still a little blood. I'm a little sore but that's normal. Is this normal? Should I be freaking out?! This has never happened before, and like I said we have been having anal sex for awhile! Please help...