You're fine probably just popped your cherry. Did you stop bleeding?
I'm thinking since you had sex several times within a very short amount of time, it's quite possibly normal since you likely never had time to stop bleeding. My boyfriend and I had our first time then it was about 5-7 days before we did it again, so I'd fully stopped bleeding. I bled again my next two times, but again, we had time between each time for me to heal.
It is concerning that it is hurting you now, though. I would consider making a gynecology appointment just because of the pain. It could be that his nails did scrape you (When my boyfriend's nails are too long, I've had instances where I've had *a little* blood.), but it's not the whole cause of bleeding. I'd wager the bleeding is because of so many times in a 7-day period not providing time for you to heal up.