I think your boyfriend might be a jerk. I think you have every right to be worried about THAT! And if you don't stop bleeding soon, see a doctor ...
i think you're ok. If he has a large penis and your cooter is not used to such a large thing envading it, then you will stretch a lot and in the process you may bleed a little. Tell him to wear a condom. I never understood the males who have large cocks. They never want to wear condoms.