Z.S.
Hi S.,
Your daughter could have a viral infection. Have you been keeping her hydrated? Be sure to give her plenty to drink since she is having loose stools. You might want to give her some electrolyte drinks (for kids) and we've even had my son drink 7up or Sprite (it just works!).
And put her on the BRAT diet for now: Bananas, Rice, Applesauce, Toast. Hope she starts feeling well soon!