I hear your struggle and your heartbreak - but it sounds like your health is placing you between a rock and a hard place. With the kiddies losing interest, the pup is pretty much relegated to living in the x-pen - and I can tell it's already killing you.
If you can't give the pup the love/affection/touching/caring that it needs - and you've tried everything in terms of medications - then my suggestion, at that point, would be to do the right thing by the puppy (esp. since he is still young and able to bond w/ another family without much damage yet) and give him a new home.
I know it hurts, but you don't want to the pup to spend his life in an xpen, do you?
