It sounds like you are saying that from the November 27 ultrasound you were given the due date of August 6, which would suggest conception on November 13. As I keep saying, it is very close, get a DNA test when the baby is born.
Sorry Annie i asked the same question again. I mistakenly gave you wrong a date of my first ultra sound test. It was on 27 November not December and the ultra sound picture only capture a pocket (no body parts at all). The doctor said I am 2 weeks - 3 weeks pregnant and my baby is due on 6 August.
As I suggested before, you should get a DNA test when the baby arrives, at least with the friend, preferably with both guys if you can do so without huge problems in your relationship with your husband, just to put the issue to rest in your mind. It's very close.
From your explanation before, which mentioned an eighth-week ultrasound rather than the one on May 7, it sounded like you conceived around November 9, give or take a few days. There is a margin for error in your eighth week, but it is probably not quite enough to stretch to the 15th if your earliest ultrasound said you conceived around the 9th. If conception was months ago, what an ultrasound says on May 7 does not help you with dating anything. Babies can grow at different rates, and though they all begin as one cell, the further along the pregnancy is, the less accurate an ultrasound is for estimating the date of conception.