i have anemia, and i suffer from these "about to blackout" episodes too. it almost always happens when i sit up or stand up, no matter how slow i go to help the blood get to my head it always happens. i do actually black out occasionally, always when i am doing exercise of some sort (i did it once when riding a horse and i blackout sometimes at marching band practice). you might have anemia, you might not. maybe you just have that balance disorder... im not sure what it is but something like where your head moves the fluids in your ears never balance out your body correctly. i would see a doctor, and maybe get some blood work done to see if you do have anemia.