You need to see your vet as soon as possible as it sounds like they need help. Only they can tell you what the problem is and what can be done for your pup. That can be anything from a parasite to toxicity to infection to internal blockage to organ failure to name a few.
The dog needs the attention of a vet....the best to you
That is what you call distemper you need to go to you're local co-op and get the puppy shot's that is if it's not to late