question about conception date/possibility of 2 different men being the father?

[rexasaurus]

firstly, please no judging or immature responses.

have been with my s/o for 3 years.

my due date is February 20th, 2014.

first ultrasound on June 22nd, 2013 dated me at 5 weeks, 1 day.

lmp was May 16th-May 21st 2013, (my cycles run about 31-32 days instead of 28).

had a lapse in judgement on May 15th, 2013 due to an argument with s/o. unprotected, but made him pull out.

now, seeing as the other man pulled out the day before lmp, I had a regularly scheduled period for the correct length of time (I've kept track for a couple years, so I knew it was coming), and my u/s & due date put my conception date around the very end of May, first day of June, likelihood of my baby being my s/o's makes much more sense than the one night stand, right?

please refrain from the 'only a DNA test after she's born will tell you for sure' responses.

also, another stupid question I know, but I'm Mexican, s/o is African American & one night stand was Caucasian. my mother suggested trying 3d u/s, to try to notice African American features, but I don't find that very likely to work. what do you think?

can I get some feedback to both questions? it would be greatly appreciated.

 

[OurLilFlu]

Our due dates are basically the same, conception is basically may 31/June 1... And if your scans have always been bang on with the same due date or gestation, it's fairly positive your s/o is the father. Hope you guys are doing better now...