If your dog appears to be upset around your child, then follow these steps from Claire Arrowsmith...
(Q) My puppy has a lovely temperament but he keeps growling at my 11-year-old son. My son tries his best to play with him but he just growls which is upsetting him.
(A) Behaviourist Claire Arrowsmith says: Growling is your puppy's way of asking your son to give him space. Although your son may not have meant it, perhaps something he has done has been interpreted as unpleasant by your puppy.
I advise that your son stops trying hard to play for a while, since often giving the dog space to realise that there is no threat is the fastest way to repair relationships. Instead, get your son to place your puppy's food bowl down at mealtimes, to toss him treats, and to engage in retrieve games where your puppy can play without having to have direct contact. He should avoid chasing your puppy, bending right over him, and lifting him up until your puppy is more comfortable.
There are many dog-child resources that you can read. The Association of Pet Behaviour Counsellors has compiled a useful resource; visit www.apbc.org.uk/info/dog_safety_information.