I was taken advantage of on July 17... I took a test on the 27th and it was negative.. My boyfriend came to town the 27th.. We had sex early morning on the 28th... (no protection either times) He was up all week and we had sex a few times.. I took another pregnancy test on Aug. 8 and it was negative.. the following week i was supposed to get my period and i spotted.. I took a test on Aug 14 and it was positive.. I have had 2 ultra sounds.. One told me my due date was April 23, 2015.. and after my first trimester ultrasound (oct 13 2014) it said I was 13 weeks, making my due date April 20, 2015.. My question is, is there any possibility that it is not my boyfriends