Hi! Good morning. i am Dr Shareef answering your query. With the history of eating outside in a birthday party followed by abdominal pain and vomiting, the most probable diagnosis one could think of is a food poisoning. If the vomiting continues, and she feels thirsty, this shows that she might be heading towards a status of dehydration. In that case, I would suggest you to take her to an ER of the nearest hospital for a clinical assessment, related investigations and appropriate treatment. I hope this information would help you in discussing with your family physician/treating doctor in further management of your problem. Please do not hesitate to ask in case of any further doubts. Thanks for choosing health care magic to clear doubts on your health problems. Wishing you an early recovery. Dr Shareef.