The scan date is what is called the gestational age. To find the conception date, cont Bach the gestational age minus 14 days. So 7 weeks 4 days from the scan date. These dates are accurate to within 3 or 4 days at this stage.
I think this date is around March 3 ( you do not say what day you had your scan).
So it is by far the most likely that Mr Feb 26,27,29 got you pregnant.