My 14 Yo Daughter Came Home From School Day Before

My 14 yo daughter came home from school day before yesterday and suddenly felt ill and vomited. Over the next 15 hours she vomited 25 times. She also complained of persistent hiccups and a bad headache. She did not run a fever. Then she went 40 hours with no bomiting and no other symptoms. Tonight at 9:00pm she vomited again and has vomited two more times since (about once per hour). She also said her hiccups came back for a short time. Any idea what might be going on?