what is making me feel really dizzy when I sit down or lay my head back?

i have vertigo, that does it. it sux

I'm not a doctor, but sometimes a low blood pressure will make you feel dizzy/faint when you sit down, stand up, or lean forward/back.

Vasovagal syncope can be causing this. Ask your doctor to do some tests for it. Have you ever fainted before or herd a loud ringing in your ears? Also have you ever seen little black spots getting out of she shower or getting up?

This can also be a sign of dehydration. Remember to do the pee test to see if your properly hydrated. If your pee is the color of water and no yellow tint to it, then your properly hydrated. If it's yellow in any way then you need to drink more and less junk food.

~RED

idk. sometimes that happens to me when i run up the stairs or sit up really quickly. it might be just the change in elevation... just a guess