What Causes Stomach Upset While On Treatment Of Allergic Sore Throat?

My 4 year old daughter appears to have pollen allergies. She is complaining of sore throat and ears, no fever, not much of a runny nose, and she has an irritated cough. I have given her children s claritin, and motrin for her sore throat and ears, run a humidifier, etc. She appears to be better, but today she complained her throat hurt again, and also her stomach. She is not running a fever (not at all during the last week when she has had allergy symptoms). She threw up at daycare around noon, last eating breakfast at 7:30 am. Would her upset stomach be related to allergies, or should I not worry unless she gets sick again (either with or without a fever)