taking the dog at 5 weeks is risky . You need to realize the dog needs lots of peace and quiet .
this "I have socialized her as much as possible and she has been to petco, vet's offices, parks, to meet my daughter's preschool class, we go on daily walks, etc." is FAR TOO MUCH -- over whelming , over stimulating , more than the pup can process.
go see rethinking "popular" early socialization
on this "I would also have the person give her treats when they meet her." I would not . Meeting a person is merely being in the presence of that other person. Brief , not close and cloying --
recommend this book again , Fired UP , Frantic and Freaked Out