hello ive found out i am pregnant! .. so heres a little detail before my question ... me and my partner have been havin sex since march 27th and i havent had sex with anyone else since february... i went and got an ultrasound done on april 29th and they said i was about 5 weeks and 6 days to 6 weeks pregnant .. now my partner is saying its not his because its only been 4 weeks since our first time... so my question is can the ultrasound be wrong? i mean i know hes the father how do i explain to him ?