I don't have my scans to hand however I would say try not to worry too much. (Hard I know)
I'm small and always measure small. Had numerous growth scans throughout all three of my pregnancies, my largest FH was 33, bearing in mind two out of three of mine were 2 weeks overdue too.
DD1: growth scans indicated 6lb7oz, weighed 5lb5oz at T+10 by em c/s
DS: growth scans Indictated 'maximum 6lb'er' plus c-section birth booked automatically at T+14, was 7lb8oz at T+13 VBAC
DD2: (my 'newbie') growth scans estimated 6lb7oz (can't remember the margins without digging my paperwork out) and they didn't want to let me go over. Began giving me sweeps from 38 weeks. I went for my final attempted sweep bang on 39 weeks. They didn't think it would do any good, i wasn't favourable but the MW's were doing as the consultant said. Attempted the sweep, couldn't get anywhere. Decided to hook me up to the monitor whilst we waited for the consultant. They couldn't find her heartbeat, only mine. Whipped me off for a scan and discovered it was hers, just really slow. Wouldn't let me off the bed, wheeled me straight to a room, prepped me for theatre and I had a baby within 20 minutes. Luckiest day of my life as it was 2 days before Xmas, nothing was happening and I had to get on. She was 5lb 3oz. I measured 28, 32, 27 in one afternoon so FH's really aren't that accurate either.
As you can see, comparing against other peoples really won't help, the scans aren't all that accurate.
I do hope you don't worry yourself all night :(