He is so cute
Looks like a new baby.
He may be lonely, cause he is in a new enviroment.
That is typical.
I recommend to new owners a stuff animal for the puppy, especially at night time.
It won't hurt to cuddle with him more than normal, until he gets use to his new home.
As for food, when your cuddling with him, hand feed him a few pieces.
I also agree a little water, makes it more apealing to the puppy.