I'm pergnant and I don't know who's the father ove my unboring....me and my boyfriend broke up I sleep with guy number one Feb. 12th February. 13th 2016....never meet this guy again after that...then got back with my ex boyfriend march 14th had sex with him march 14th March 15th March 16 march 17th March 18th....found out i was pergnant april 25th...didn't know if I had a period February or March...did a early ultrasound may 8th it said I was 7weeks n 4days...drs r going by my last period witch i guessed march 15th the 1st ultrasound said I was 3 days off my due day so from my period my due date is December 20th 2016 and ultrasound due date is December 23rd 2016 what should I go by and who would be the father....