sick puppy..... help?

If you're that concerned, the emergency vet is likely open. Puppies need nutrients, a puppy not eating or drinking for even a day or two can get dangerous. Dry heaving and/or pooping nothing but mucus sounds like it could be a bowel obstruction but I have no vet experience at all so I really can't say. I've read people will try to get some water into their dog with chicken broth (low or no added salt or homemade if you've got it). It gets some fluids at least into your dog so they don't dehydrate. As far as food goes, you can try boiled chicken and/or rice and see if he can keep those down as they're usually pretty easy on the tummy.

As Anon said, a trip to the vet is the only answer. A 7 week old pup is nothing to play games with and Dobiegal is NOT a vet! DO NOT LISTEN TO HER! Do an internet search for your area for an emergency vet and get him there as soon as possible.

Don't feed him anything for 24 hours except water. Then give small amounts of boiled rice and if that stays down, give some boiled, unsalted chicken meat, and slowly incorporate his food into that. The mucus is a sloughing of the intestinal lining, which is why you don't want him to eat solid food, let the intestine rest. Could be a reaction, but I doubt it. It's probably gastroenteritis.