15 year old with sickness in the morning

My 15 year old daughter wakes up at around 6:00 every morning for the past week with vomiting and diarrhea. She is not sexually active so we have ruled out the possibility of it being from pregnancy. we also thought it might be anxiety but it is Christmas brake and she doesn’t feel nervous or anxious about anything. The symptoms go away around noon unless she Eats too much. We have tried some kaopectate but it only helps temporarily.