My bulldog is 6 years old. She has lots of problems with crystals in her urinary tract and has to eat Hills Science Diet CD dog food which is a prescription dog food from her vet. This food doesn’t seem to set well with her stomach and causes her to be constapated. Today she was acting like her bottom was bothering her so I got her wipes and was going to clean from under her pig tail. When I started she cryed from pain and I noticed that either her tail has gone up into her rectum or either it has swelled out around it. Any ideas as to what’s going on?