I am a 20 year old female who, for several years now, expierience lightheadedness, dizziness, blurred vision (sometimes temporary blindness), arms/hands shaking or convolsing upon standing up. It has been a problem for about 2 years and happened about once a week. As of late it happens literally everh time I stand up and no matter how slow I get up or what I do I have to hold onto something, if not sit down, to avoid passing out. I would love to know what is wrong with me and what I should do ? Please help! -dizzy in the army.