When was the ultrasound (calendar date) that said you were 8 weeks pregnant, and what due date did it give you?
Your ultrasound in September would have said you were four weeks further along if you got pregnant in late June. It sounds like you got pregnant around July 28-30, which makes sense with a period coming July 15. Don't worry, Mr. June is so far from being a candidate that he may as well have been Mr. Two Years ago. Congratulations on your pregnancy. : )