Hello, and welcome to Just Answer. I'm sorry to hear that Fudge is having this problem. There are a couple of things that could be going on with him. We ca see these signs in dogs that have eaten something outvside their normal diet that has caused a disturbance in the natural bacterial balance. Another possibility in a 5 month old pup would be internal parasites.
Both of these possibilities are just as likely. You can try giving a little Pepto Bismol or Kaopectate at 1/2 teaspoon per 10 pounds, so I would guess Fudge's dose would be around a 1/4 teaspoon. This can be repeated every 8 hours as needed.
If ther is no improvment by Monday, I would recommend a vet visit to have him tested for internal parasites.