Blood during sex?

I had sex last night for only the second time ever (the first time was like 2 years ago and was kinda traumatic) and it went fine but afterwards I was bleeding lowkey a lot. I know that didn’t happen the first time. Is it because I don’t ever penetrate myself when I masturbate so I’m just not used to it? I genuinely don’t know if it’s normal or not and it definitely concerned the boy I was with (and me too but I stayed calm because it was his first time and I didn’t want him to freak out). Please help!