Had Stomach Cramps,nausea,vomiting And Fainting.Reason?

19 yr old daughter just called. she has had another 'attack'. seems to be about once a month, for a total of 3 respectfully. she gets stomach cramps, very dizzy, feeling of high fever/very hot with excessive sweating to the point of drops of water fall to floor, nausea and vomiting and fainting. only cure is to lie on cold floor, not her bed or couch, with a blanket until symptoms go away...usually 1-4 hours. the next day she may have tender stomach from cramps, but otherwise is okay. ANY IDEA? thanks, from a concern/worried and confused mom.