Destinydeberry:
I just want to mention in case you haven't read, if/when you decide to switch food, you should do it slowly. Add little of the new food mixed with the current, see how the pup does, if she seems ok with it, add little more, replacing with the old (purina). If you can't decide on which, I suggest you contact the manufacturer. Some companies will send you a small sample to try, others will give you coupons. I hope your pup feels better soon.
Mimimomo:
I actually didn't think about that part... When she mentioned Purina, I automatically thought "not good food" so I wanted to mention perhaps a change. lol Thanks for pointing that out.