I wouldn't worry. The barking will come when he gets more comfortable with his surroundings - at some point that he will "find his voice". Cherish the silence.
As far as the not drinking is concerned - it's a little more worrisome, but definitely not serious. As long as he's excreting regularly - he's getting his fluid somewhere. Are you feeding him wet or dry food? If you're only feeding him dry (which is actually recommended for dogs - esp. small ones) and he's not drinking, you might be a little concerned.
I'm sure you're a great doggy mommy, Nephy. Plus, according to today's news,
owning a dog is beneficial to your health.