Dont know what this is

My SO and i had sex last week while glow showed i was ovulating and fertile. CM matches that as it was ewcm. He finished in me. We just had sex tonight and i had very slight bleeding just pinkish. Im not due for my period for another week. I like it rough but have never bled from sex cause of that so this is unusual for me. Ive been cramping a little as well. What may be the cause of the bleeding?