Crying after intimacy

Me and my boyfriend have been together for almost one year and last night when we were together we got intimate. We didn’t go all the way, he went down on me and fingered (for lack of better word) me. It was a nice feeling and this has been the second time we’ve done it, but whenever I looked down at my leg there was blood. I really started internally freaking out and I went to the restroom and cried on the toilet. The first time we did this I didn’t bleed but I definitely felt the need to cry in his arms after. I found a little bit more blood on my leg and started cleaning myself frantically with baby wipes and I wanted to scrub my skin raw. Needless to say it was a horrible feeling. Whenever I was done with the restroom we had decided to stop what we were doing and start something else when I started crying in front of him. I don’t really know why I was crying because I wanted to be with him and I didn’t mind what we did. But I couldn’t stop I don’t know why. He told me he was sorry and tried to make me feel better which I did for a little… then I started crying again. Eventually I stopped and we went on a drive where he told me that he felt guilty and that he felt he had taken advantage of me or something (which he didn’t). I feel better now but I’m wondering why I cried so much when I know that blood is something that can show up. And I also don’t know how to help comfort him. I feel like it was better to cry in front of him then do it alone at night but I don’t know how to ease his mind that he didn’t hurt me or do something that was unwanted.. does anyone have any advice?