A little pup like that should be full of life, curiosity and action.
The fact that she is NOT, shows that something is wrong.
Usually with a pup, if an injury is minor, that doesn't stop them in their tracks!
But when something is more serious, a sign is that they become very quiet and lethargic.
My advice is to seek a second opinion if your pup is no better.
I am sorry your puppy is hurt. You should have told your Vet you wanted the pup checked. There is no way to be able to tell you what may or may not be wrong. If you are that concerned and the pup just seems too quiet, I suggest you have an ER Vet check it. If you don't do that and the pup is no better tomorrow, taje it into your Vet to be checked.
If the pup continues to sleep, walks with an unsteady gait, starts vomiting, etc, you need to get it to a Vet ASAP.