I'm sorry to hear that she's been having diarrhea problems but I'm glad to now hear that she's doing much better. I was also going to say that you should get a second opinion. I don't have a dog but my RB cat Starr was diagnosed with both Colitis and IBD. I tried so many different kinds of cat foods but nothing seemed to work. He ended up having to be put on prednisolone for the rest of his life which unfortunately made him gain too much weight. Hopefully Autumn won't need to be put on any kind of drugs and you'll be able to control her problem with diet. Lots of prayers and positive thoughts are being sent her way.