Are ultrasound conception dates accurate?

[tina6146]

I discovered I was pregnant unexpectedly, and went to have an ultrasound on May 23rd. Due to having wavering periods, I never really keep track, and therefore I don't know when my last period was. I can give an "estimate" but I really don't know because I never keep track. (Plus I have always been told that because of metabolic issues, and PCOS that it would be very hard for me to get pregnant).
Anyway, not exactly proud of this, but I was with 2 different men in a two week time period. One I didn't use protection with on Saturday April 7th (we have been very good friends for years, and it just happened on a night out drinking/dancing) and the other man I only went out with a few times, and when we slept together the following week (on Saturday April 14th), the condom broke. I didn't think anything of it, because I am almost 38, and this has never happened to me before.
So, my question is, when I went to have my ultrasound, the sonographer did 2 measurements for the conception date: one was 6 weeks and 3 days, and the other one (just to be sure) was 6 weeks 5 days. So, we split the difference and said 6 weeks 4 days. This would make my conception date April 7th, which is the exact night I was with the first man.
Do you think there's a big chance that the 2nd man could potentially be the father? I am hoping the first man is indeed the father, because we have been friends for years, and it would be alot easier to handle. The second man, however, I don't even speak to anymore. I would hate for it to be the second man.
Any advice on people that have gone through this? I guess I just want some confirmation that these ultrasound dates are accurate. The ultrasound tech was amazing, and I feel like she really knew what she was doing, but I just want to make sure that these results couldn't be a whole 7-8 days off.

[doomed23]

I hope that made sense!!

[doomed23]

Yes, my midwife told me that I was 11 weeks along on November 4th. On that day she calculated that my due date was May 24th. Even though I told her that i had a lmp date of September 1st.

[AnnieBrooke]

I guess I'm also a bit thrown by this part  " I had an ultrasound with a midwife November 4th and she stated I was 11 weeks along with a due date on May 24th."  If someone had an ultrasound on November 4 that said she was 11 weeks 0 days, she would be due on May 28, I think.

[AnnieBrooke]

I was just a little thrown by you saying "but at my first ultrasound having a due date of June 7th would have put me at 9 weeks along NOT 11."  

[AnnieBrooke]

At what point in the pregnancy was the ultrasound that gave you a due date of May 24, was that at 11 weeks?

[doomed23]

The ultrasound gave me a due date of May 24th. Thanks for responding.