30 weeks & spotting

I had my cervix checked today because of strong cramps. They said spotting afterwards could be expected. I went to the bathroom & wiped, i had mucus like discharge that was pink and two small red clots. I’m also O-, but I had my second rhogam shot two, almost three, weeks ago. Is this normal? I don’t want my body to start having an adverse affect on her because of my blood type and me spotting. I also haven’t had mucus like discharge since the beginning of my pregnancy.