I always measured bigger when they measured my stomach by measuring tape. At my last u/s at 32 weeks the baby was measuring bigger than average too. I ended up having a 8lb, 6oz boy .A.N.D having 2 amniotic sacs. So I measured bigger either way.

That said it could be a number of reasons why you're measuring bigger. Maybe you'll have a big baby! :)

Did they say extra sac could have been a reobsorbed twin??

I guess that's the word. ??? ( it's a french hosp!) lol they siad it was possible I was preggers with twins and one never developped cause when I had my first u/s I was only 5 weeks and there was only 1. So who knows. I have a gorgeous healthy (a lil overly healthy-lol) boy!

Yeah from what I heard of on this dr show, it happens really early in the pregnancy. But like I mentioned in the post with your pic. My ex- lost a twin around 3 mos and his girl miscarried it, to carry the other one to term.
They say 15% of all pregnancy's start out twins and the woman never know cuz they reobsorb early, or never develop at all.