Using the "weigh mama holding babe/weigh mama alone" technique Torin is 14 lbs exactly at 5 weeks 2 days.
He was 9lbs 8oz at birth and he wears size 2 huggies (we sposie at night) and 3-6 month outfits. Actually, a few of the smaller 3-6 items don't really fit anymore, and some of the smaller 6-9mo stuff do. I've had to weed through his clothing already!
Talula- I've treated all my kiddos the same in terms of nursing on demand and they've all been about the same size at birth (dd1-9lbs6oz, dd2-9lbs, ds-9lbs8oz). But while dd1 and ds took their head start and ran with it, packing on the baby pounds dd2 did the opposite and dropped right off the weight charts until finally pulling herself up to the 10% around a year. Same breastmilk, same parents, totally different outcome! So I wouldn't worry that other kiddos are gaining faster. I think it's Dr Gordon who has the "watch the baby, not the scale" quote? As long as your little one is eating well, producing diapers, and acting happy then it's all good. And you'll get more use out of those adorable 0-3 outfits!