UpdateJust had my ultrasound appointment yesterday. Even though I was told repeatedly that US's can be off by as much as a pound either way, they estimate the baby's weight to be 7 lbs 3 oz... much better than my OB's guess of high 5's! The amniotic fluid also measured in at 15 cc's (right in the mid range... anything under 5 is worrisome.). So, yes, looks like I was measuring small just because he had dropped so much!
My internal revealed 2 cm dilation and 80% effacement, too, so he is definitely getting lower... hooray!
So, like you all said... nothing to worry about! Thanks for the support!!