Anyone measure late despite knowing when you O'ed?

mckenya

We used Clomid + trigger to get pregnant so I know within 48 hours when we ovulated.  Last week at 5w4d, I only measured 4w6d and there was only a gestational sac, no yolk sac, no HB.  My doctor said I probably just didn't know when I ovulated but obviously I did!  He also mentioned late implantation but I was getting BFP by 9 DPO so I don't know how it's that.

 

My HCG was 19,900 at the same appointment which again puts me more in the 5 week range.  I'm just freaking out because I KNOW when I ovulated and feel like measuring behind is a pretty bad sign.  Anyone have any positive stories to share?