A puppy crying in the middle of the night for days on end can be a very frustrating situation. Try to relax and remember that puppies only cry for a few reasons.
Since your pup is in a new environment, away from his siblings and his mother, he feels very scared and alone. You can ease this shopping by buying one of those heartbeat stuffed animals for babies and putting it in his box with him. This will comfort your pup and lull him to sleep.
Another reason why your puppy will cry is because he is hungry. Make sure you feed your puppy enough and that he is not hungry. It will be very difficult for your puppy to function and he will become very irritable if he is not being fed enough.
If you notice your pup crying when you’re out of sight, she may be experiencing separation anxiety. When they cry, don’t always come back to them, talk to them from the other room instead. This will reassure them that you haven’t abandoned them and they will gradually accept you leaving the room.
Make sure your pup stays at a comfortable temperature; you don’t want them to be too hot or too cold. For example, if the temperature has recently dropped, your pup may be cold, so he may want to invest in a small sweater to make him more comfortable.
Remember that puppies are babies and, like human babies, they will fight sleepiness and get cranky. If your puppy is sleepy, put him in his cage with his heartbeat simulating a stuffed animal. Remove them from the main area of the house where all the action is so they can get some rest.
If your pup isn’t comforted by anything you do, he may be sick. You will need to see your vet to make sure your pup is not sick.
Also like babies, puppies will cry if they see that it will get their attention or whatever they want. The way to avoid this is to check that none of the reasons listed above are possible. If they are not hot, cold, tired, afraid or lonely, let them cry. Once they find out that crying isn’t going to get them, they’ll stop.
Good luck