You've gotten some good advice here. First, congrats on your new baby and WELCOME to YT.
I am really glad you found us because your new yorkie is
truly at risk right now
. Not only was he taken from his Mom wayyyyyy too early, but he has fleas (dangerous at such a vulnerable age), he was vaccinated TOO early, he was vaccinated when his immune system is fighting something already.
He
needs to see a vet ASAP -- as in, tomorrow is not soon enough - to be frank.
Exactly what vaccines were given?
Don't bathe him anymore -- keep him warm, hydrated, and fed - and get to a vet asap. If he gets shaky or weak - give some Karo Syrup, Nutrical, or even pancake syrup in an emergency. You should keep Nutrical on hand at all times for puppies, imo.