My puppy is vomiting n runny poop bad breath regurgitating food weight loss loss of apatite.

Stop feeding it whatever you are feeding it, but give it water or sugar water to keep the puppy hydrated. It can be the parvo virus and it is a very serious condition in canines especially in puppies. If your puppy did not receive a vaccination for this condition and if the puppy has the parvo virus, there's a chance it might not survive. It might also indicate the food is too rich and your puppy needs to be on a bland diet. I hope you have been feeding it puppy food only. Google the brand name and see if there has been a recall on the puppy brand which might be an indication the food is contaminated. It is important to keep the puppy hydrated and electrolytes up. Call your veterinarian for advice and the possibility of being hospitalized for treatment for parvo, if it is this. The parvo virus is contagious so keep puppy away from other canines until you know it isn't this virus. Keep fresh water available and if not drinking on its own use a dropper to give him water/sugar water. Prepare homemade boiled white rice and boiled chicken or boiled hamburger (twice as much rice as chicken or hamburger such as 2/3 boiled rice & 1/3 boiled chicken or boiled hamburger.) Take care of your puppy the best you can and CALL your VET ASAP.

Has your pup been to the vet and has he been vaccinated for Parvo? Stinky, runny poop is usually a sign that indicates Parvo. This is a horrible illness that can kill quite quickly. Time to make an emergency trip to the vet.