You should really see a docter, for me Ive had a headache these past couple days but there not that bad but I also havent been sleeping these past couple days and I get tons of excercise and work. Make sure you get some good sleep and try going swimming and doing some laps but dont go into really cold or warm water. Also eat healthy, vitamin c and eat friut, pattasium which is in bananas can really help it can make the difference whether or not you get light headed or not, you know all this Im sure but man all this stuff really works for me. Dont oversleep or watch or play to many videogames and dont do any of these in really dark rooms where there is little light all of these could be reasons.
Im telling you out of experience, I use to get them alot, almost everyday I think I dont know if there was something wrong or not but make sure you get that checked. Serious.
Anyways I wish you well.