Sadly you really are never to young I have found I got my first Migraines by the age of 6. most likly it was probably triggerd by the change in the atmosheric pressure although thier may have been underlying ones as well. Be sure to go to the doctor so they can try to help although honestly you may have to wait to get another one to get a better idea of the type that it really is and if it leans more towards a silent migraine, ice pick or occular. It is also possible that it could have been slightly triggered from low blood sugar since you mentioned that you felt a little better after having some water. Which feeling hot and dizzy and a little faint is what happens to me if i havent eatten in a couple hours even though I am not diabetic. First thing they will ask you is to keep a food diary so i would recommend starting that as soon as possible so that even if you go to the doctor in a day or two you have something to start with.