I need ADVICE BADLY!

I’ve been seeing this guy who is two years younger than me. We started sleeping together and last week when I started my period, we started having sex and I stopped him and told him that I was on my cycle, he said it was fine. But when we were done, he saw blood on him and he threw up. Now he’s weirded out by it and feels weird around me. But I don’t feel weird around him. What do I do?