Anal & Period?

Okay so I just got off my period or at least I didn't bleed all day today. But my periods are super weird. It stops then goes away then comes back and stops. Well I had it for 4 days it stopped for a couple hours yesterday, came back last night then it was gone all day today. Me and my boyfriend went to have sex just now and everything was okay. He finished and we went for round 2 but anal this time and whenever he was done there was literally a puddle of blood in my vagina. Super scared at the moment. Idk if it's my period coming back. Or if he like ripped something really bad. My ass don't really hurt just a little sore bc it's like our 4th time doing anal. What y'all think it could be? Helpppp.