Why do i keep blacking out?

This is really weird... it happens when I stand up after sitting down for a while or I suddenly see a bright light.
I start going dizzy and my head and eyes start to hurt really badly... they get really tense. Then everything goes black.
After about 5...

seconds it stops and I'm back too normal, only slightly dizzy.
Do you have any idea why it happens?
Its extremely painful! I drink a lot but I don't eat much usually but when I do eat a lot it still happens.

you need to talk to a dr, could have something to do with your bp, could be your blood sugar...

when you stand up suddenly, something happens with your blood, and oxygen to your brain...

you really should see someone, it's not normal

Having iron deficiency anemia may cause you to feel tired and often look pale. It's a common type of anemia — a condition in which blood lacks adequate healthy red blood cells, which carry oxygen to tissues. Oxygenated blood gives your body energy and your skin a healthy color.
As the name implies, iron deficiency anemia is due to insufficient iron. Your body needs the element iron to make hemoglobin, a substance in red blood cells that enables them to carry oxygen.
Iron deficiency anemia is common, especially in women. One in five women and half of all pregnant women are iron deficient. Lack of iron in your diet is one cause of iron deficiency anemia, but there are other causes as well.
You can usually correct iron deficiency anemia with iron supplementation. Sometimes, additional treatments are necessary, especially if you're bleeding internally.
This sounds like what used to happen to me, occasionally it will occur if I do not get enough iron. Hope this helps, you should go see a doctor as well.

Ooo thanks

If it weren't for the pain, I'd say that it might be just growing pains, or even a sign of pre-diabetes. However the pain makes me think it might be something more serious. You really should be examined by a doctor and maybe have your head x-rayed.

Yeah... this happens to me too... I have no clue but, YOUR NOT ALONE!

I do the same thing about once or twice every
couple of days. I told my mom about it she thinks I
need to go to an eye doctor. I think you need to too.
Sometimes it may happen when you stand in one spot
too long. Try drinking a lot of water, thats what I do.