What Causes Dizziness, Headaches And Migraines?

Hi im a 17 male and 6 foot around 165 lbs for the past week or so i have been really dizzy and shaky. but it is not a constent thing, just comes and go. i also wake up dizzy but i can't figure out why.i also get headaches that sometimes turn into migrains. i drink lots of water and eat kinda regularly. i am very active. i would really appricate your help.