Woah...you have a pup that is only 5-6 weeks old!?!?
That is WAY to early for a puppy--ANY puppy--to have been placed by a breeder. Most reputable breeders agree that 12 weeks is the ideal age. Also, not sure where South Beach is, but early placement is actually ILLEGAL in many states.
At this point, I would have to agree with the above post(s)--I would take this little one to the vet ASAP. Also as mentioned, what you are describing very well sounds like it could be a hernia.