Hello, I Was Almost 19 Weeks With Twins And They

Hello, I was almost 19 weeks with twins and they dies at 18weeks. I had sex 4 days before I went to the ER and found out the babies died. They were really small so the Doc PERFORMED a D and E. I didn't have intercourse since that day. Is it a possibility that I can be pregnant. They say sperm can live in you up to 5 days