late pregnancy sex

I'm 37 weeks today and had sex earlier, kinda rough. I'm 2cm dilated, 70% effaced and lost my mucus plug. After having sex, I didn't have a lot of his semen come back out of me. 4-5 hours later, it came out but was accompanied by some brown blood. Not a lot just a few little spots and it was dried like old blood. I read that it's normal because it could've irritated the cervix. Anybody else doing this?