Since last night my 4 year old sister has been having on and off stomach aches. She has been eatting but not as good. When she would have one she would hold her stomach and say my tummy hurts off and on. She would walk holding her stomach hunched over. Now today she has been doing the same thing. Just not herself at all. And now she is vomiting. She has 5 times and now dry heaving. Shes very out of it. Wont really answer to us. Now this afternoon she was swimming and jumping on the trampoline. Having complained of a stomach ache all morning and night. She doesnt have a high temp. Maybe 100 F. Do you think she could have an appendicititis. I had one back in November and I was like her but not vomiting. Also this afternoon she passed a yellow stool and was sort of are loose. What should we do?? What does this sound like.