S.S.
Well, I would say you have nothing to worry about. :)
My first was a girl, always measured small, they then told me (when looking at her after birth) they thought she was about 7 lb 12 oz. then they weighed her and she was 6lb 13oz. They were only a pound off! :) hee hee
Baby #2 (boy) was 6lb 14.5oz and they thought he would be about 7.5lb. I measured large with him.
Baby #3 (boy) was 6lb 13 oz again and measured small at the end also.
Baby #4 (girl) estimated to be around 7lbs and measured right on the whole time and came out 7lb 4oz.
All 4 had decreased movement the last 2 or 3 weeks of pregnancy because their space got too tight for movement. If you are a smaller person they tend to still try and group you into the same category as regular sized people and freak you out that something is wrong, when really, small people...have small babies. :) Thank goodness!
Bottom line...
They will all be different, you trust your own mommy instincts and if you think something is wrong have it checked out, it's okay to over react a little bit, it's a brand new little human for crying out loud! :) I pray everything will be wonderful for you and you will just have some fun stories to tell as they get older. :)
PS. Hoola hooping with your hips (no need for actual hoola hoop) to kick start contractions is good, but generally speaking...if baby doesn't want to come out yet, she isn't going to like you bugging her about it. :)