My 5 Year-old Daughter Woke Up Complaining Of Stomach Pain.

My 5 year-old daughter woke up complaining of stomach pain. She went to school and I received a call a few hours later that she got sick. I brought her home and she has gotten sick a few more times and its a white foam. Any thing she drinks or eats comes back up a few minutes later. Should I be concerted or is it just a stomach bug?