Light pink spotting and cramping!

Jacinta • Pregnant with my rainbow baby boy ☺️💙👶🏽🌈 due December 27th 2015!
I was feeling really off today and woke up at noon then took another nap at like 3 pm and was cramping really bad off and on! I had sex earlier but when I went to the restroom after my nap I wiped and there was pink blood when I wiped! I'm still cramping, feels like menstrual cramps! What could this be? I'm 38w3d!