Due date: LMP v. ultrasound

ahamm2006

I had my first ultrasound this morning and saw the heartbeat (122 bpm)! It was awesome, and I am even more excited now than before!

They are saying that I am about 6 weeks along, but my LMP says I am 8w3d. I had been off the pill for a couple of months and gotten back on it last month, before I missed my period. The doc says this may have skewed my ovulation. My due date jumped from June 17 to July 4. I'm still a little confused as to how this works and which due date I should follow. I go back in 4 weeks for all the fun bloodwork and physical.

Has anyone else had this happen?