how long did your period last ?
Using an ultrasound from the 12th week of pregnancy means you need to add +/- 7 days to all the dates below, but even so it definitely does not sound like Mister September 1 had anything to do with anything. Here is what the conception calculator says about your due date of June 14.
Computed first day of last menstrual period: September 7
Probable date of ovulation: September 21
Possible dates of conception: September 17 to 25
Due date: June 14 (40 weeks)
Given that your due date came from a 12th week ultrasound, and even if we use the slight discrepancy with the date of your period to assume it might be a few days off (to be expected when the margin for error is 7 days) I'd say you did not get pregnant any earlier than September 17.
Thanks I didnt think the 1st could have anything to do with it! Just wanted someone else's view on it!