Bloody sex

I don't know who am I gonna talk to about this, so I post here again. Hope someone will help me.

Last night, I had sex with my boyfriend. It wasn't my first time actually. We've done it before, but a few weeks ago. When we meet we just keep on touching each other. So, last night, we did it again. At first, only half because it still hurts. Then, for 2 round 😳😳😳 , he push it all in. It does feels good and I think I cum 2 or 3 times. But, it really take him long. I even feel that I'm so wet down there, even him thinks the same. Then, when he flips me over, he's shocks because there's  blood in the bed. I mean, not a little stain but actually lots. Why do you think guys there's blood? I thought last night my period come but no. My undies is clean right now. Nothing hurts. But, I'm scared. Please, help me.