Period horror story

I need to rant.. last night was my junior prom and I went with my boyfriend who I love and feel very comfortable around. We were at the dance and we decided to leave early and go to a park nearby. We started making out and he was fingering me and even went down on me. We eventually went back and got in our limo to go get ice cream. While I'm sitting there with him and the rest of our group I looked down at his hand and his fingers were COVERED in blood. I panicked and grabbed his hand and had a full on panick attack in baskin robins. He thought the whole thing was funny and I was MORTIFIED. I knew I was 4 days late but my period was always late so I didn't think anything of it. I came back home and my dress was covered in blood and my mom assumed I had sex. Worst. Night. Ever. 😩😩😩