Bleeding After Sex

I am 15.5 weeks pregnant. My fiancé and I just had sex, we were in the missionary position and he was holding my legs up towards me. After sex I realized I had some blood on the bed. I went to the bathroom and wiped and it was like reddish/pink toned urine, no clumps or pure blood. I'm laying down now and getting some cramping in my pelvic area where the baby currently is (we have a fetal doppler and that's where the heart rate is). Should I be concerned?!