I second trying the pedisure to get liquids and calories, nutrients isn't as important while sick as long as hydrated, else maybe some applesauce packets even juice if needed. I would say ER if high fever, difficulty breathing\weezing or symptoms getting worse not better.
I would call the nurses line first, but you know your baby best, so if you feel you need to go, please do! Will she drink Pedisure or pedilyte?