Lately Wally's poop has been inconsistent. His diet hasn't changed at all [he's on Evo] but he seems to be a little constipated. His poop is very hard and dry and literally clumps apart and then the ends are very wet and runny. Last night I had to let him out three times because he had the runs. I don't know if he may have eaten something that upset his tummy because he's walking vacuum! Any ideas?? He has a vet appointment the first week of September, but I feel like I shouldn't wait...