Hi Elly - I'm sorry to hear Ally hasn't been well. I would not change her diet at all - rather change THK formula you are using to one of the turkey formulas. I would also highly suggest a constulation with Susan Davis - she has great supplements that have helped lots of our babies.
Pet Health Pet Nutritionist Holistic Pet
Ally probably needs to have some dietary enzymes added to her diet to allow the pancreas a chance to rest. And adding a daily probiotic is always a good thing, particularly if this began as gastritis. Many of these little guys really have issues with some form of IBD and left untreated begins to manifest as pancreatitis.
Good luck to both you and Ally and I hope she is feeling better very soon!