Miscarried now worried I'm pregnant again

So I was approximately 8 weeks when I miscarried. I started miscarrying on December 25th and I stopped bleeding 3 days ago now I just have lots of brown and pink discharge. My boyfriend and I were going to wait as we are not well emotionally but we found ourselves getting into it tonight anyways he ended up finishing in me without any protection. I read online that many women get pregnant right after a miscarrage. my boyfriend said that it was a very large load and he's worried that I am going to get pregnant again. Please help me if anyone has any experiences it would be great.