I could be sitting or laying down. In class or at home, I will feel like I am going to faint. I would have to hold myself and close my eyes. When I get up it goes all black and then normal after a couple of seconds. It mostly happens when I am sitting/laying down for more then 5 minutes. I eat normally (Even though somtimes I can go days without feeling hungry or full) Can someone please help me with this? I am only 13 years old.