When?!

My last period was Nov 19.. Glow told me my most fertile day was Dec 2 and I was feeling cramping that day so I had sex.. I had cramping the two days after sex Also.. I had sex Dec 6th also.. I'm currently 20 weeks 2 days according to ultrasound and app.. Which day did I conceive? Or did the sex I had on the 2nd or 6th made me pregnant? (Two different guys)

Doctor Did not give me a conception date!