My 3 week old DD has a very stuffy nose and it seems to be affecting her sleep because she gets all agitated and wakes up with it. We got told to not lie her on her back too much as it seems worse then and I've got her some saline nasal drops from the chemist too. Is this common in newborns or could she possibly be having an allergic reaction to the family members cat? (Her dad has cat allergies)