I had intercourse with a guy on the 6th of June... Then I had my cycle on the 18th.. Then me and my boyfriend got back together on the 29th.. I found out I was pregnant when I missed my cycle in the middle if July! The due date giving to me was march 25 2013 based on my LMP.. Then I went for an ultra sound on Halloween n they changed the due date to march 21st 2013 Just a four day difference! Who would be my child's father! Is it possible to had gotten pregnant in 12 yo 13 days n then had a cycle