My bridge boy, Keno, did this when he had a severe pancreatitis attack not too long after I adopted him. It started before bedtime one night, but having no experience with it I didn't realize what it meant. Then the diarrhea started sometime during the night and I rushed him to the vet as soon as they opened at 8:00am. He was already dehydrated by then and had to spend the night on IV's. He was in a lot of pain and gravely ill and I almost lost him. I felt horrible when I realized that the pig's ear I'd given him had caused it, but I had no idea he had problems with his pancreas. I was totally fanatical about his diet after that. He only had one other incident and that was when a sitter gave him some chicken with the fatty skin on it I was out of town overnight. Fortunately, when I got home I recognized the early symptoms right (that stretching posture) and got him to the vet before the inflammation got bad.
Sending Turbo good thoughts.