6 week question---- help

Suzanne • Proposal 11/2/14* Married 7/11/15* MC 9/6/15* BFP 11/2/15* DUE 7/15/16
Just had my early US today at 6 wks exactly and my OB seemed quite happy. He wasn't sure we would see anything at this point but we were doing it because I insisted. We saw our baby's heartbeat, which was amazing. Doc is happy and although he said the picture wasn't clear enough to measure baby's size, it was just too early and baby was definitely there. We will doing another along with all my bloodwork on December 4th, at 8 wks.
Here's the thing. OB called the next appointment my 8 week ultrasound. He said he was totally confident in this pregnancy. I thought the heartbeat looked a little slow, but it's starting to look like I have anxiety issues and can be classified as a SERIOUS worrywort. But when they gave us our paperwork, they said based on my lmp and today's ultrasound, my Edd is 7/28...?!? My lmp was 10/9, and I know I ovulated 10/23, on cd14 because of opks and bbt. I should be EXACTLY 6 weeks, based on my lmp. Should I be worried about this? They didn't say anything to me about it being abnormal, and I only found out our Edd is off by nearly 2 weeks when I looked online at the paperwork?!? I'm here worrying all over again, and I thought I'd feel better after the US :(:(:( thoughts anyone?