Hello this isn't really a health concern more of a stressful situation

I had sex with a guy may 23, 2015 then got back with my boyfriend and slept with him may 24th I got my period on the 25th it was a full and normal period

I'm currently 23 weeks pregnant due March 7th 2016 it says I concieved June 15th all my ultrasounds have been the same due date is there anyway that the baby could be the first guy I slept with baby?