If your pup is only 16 weeks, he doesn't want to be separate from you, these little guys attach very quickly, they are like babies at this age (well, all their life really
), and it wasn't too long ago he was taken from his littermates and momma.
Keep him in his crate in your room, on your bed, or nitestand right next to you where he can see you at night. I would not leave him all alone at the opposite end of the house, how lonely he must feel not knowing if you have left him or not.
I think you will find you will get much more sleep if he is close by, he will be happy and you will be happy
