I'm glad she's doing better. Yeah, some rabbits have tummy trouble due to diet, but they also can get stressed in a new environment and that can also cause digestive problems. Gradual diet changes are always best for rabbits, so it would still be good, when you get your new pellets, to gradually introduce them to your bun, with very small amounts at first, and gradually building up to the amount you plan on normally feeding each day. Just keep an eye on her poops and if they stay normal then you know she's adjusting ok to the change in food. It's pretty much like this with any new food you are going to feed your rabbit. Slow gradual changes are always the best.