Hi! I am so sorry you are going through this. I too have a little one who has been diagnosed. Zeus was diagnosed about 9 months ago and he was put on prescription diet food also. He was doing great until he got into the cats food and then he had another attack. The vet said that the cat's food had too much protein in it and his little tummy just couldn't handle it. So, we are now on Hill's RD. We stay away from treats other than greenies. So far, so good. Anytime that Zeus appears to have a tummy ache, we just give him half of a Pepcid AC, per the vets instructions, and it seems to do the trick. I would just make sure that there isn't anything around that your little one could get into. As you probably already know, once they are diagnosed, they are very easy to have another attack.
Good luck. I hope she feels better soon!