I Lost My Virginity Friday. I Don't Know If It's

I lost my virginity Friday. I don't know if it's normal to have blood three days after having sex. but that's what's been happening. I'm scared. I just found out my partner could've had an STD I'm not sure. I'm young and need help. I don't know what to do. It doesn't burn or hurt to pee, but after I pee or anything there's blood.