Did they ever test stool samples?  When I got sachi about a year ago, he had coccidia.  Wouldnt eat or drink, had to force feed him.  Vomited, slept constantly.  Once they put him on the medication for the coccidia, he improved rapidly.  But it was very tough going for a while there. 
Obviously something is wrong with your puppy and if the vet you have currently isnt helping, I would definately consider another vet.   
I know this is very scary and I wish you the best!     |