You feed according to the weight of the dog. The amount should be on the dog food package if you are feeding dog food. If you're feeding home cooked or raw . . . well, I don't know how to work that out for a little dog, someone else can help you out with that, though, I'm sure, especially if you post a question about it in the food forum.
A tired pup is a good pup! Lots of play during the day, then quiet things down an hour or so before you're going to want to go to bed.
Your pup is going to be excited and a little stressed for a while, so lots of reassurance, affection and attention will go a long way to alleviating that. BUT - when it's time for bed, it's TIME FOR BED. Don't give in to the whining or your pup will figure out that whining and crying will get you out of bed and doing what he wants you to do! If he's sleeping in a crate, you might want to keep the crate in your room so he has some security. Dogs really don't like being alone.