I'm 14 years of age and I've been getting dizzy when I stand for a while now.I would stand up get 2-5 steps and I'd just get dizzy my vision would go a little blurry but I was still in control of my body and I could still see what was going on around me . Recently these 'episodes' have been getting worse I would Stan up and take a few steps then my vision would blank out my legs would go shakes and I would shake in circle motions .After a little bit of time it was getting I the point where I'd collapse and blank out for couple minutes and I'd suddenly wake up with a headache and I could not recall what had happened but thankfully my brother would be a round and fill me in on what had happened.My latest episode was today where I stood up from my arm chair in my siblings room when my vision went blurry I started shaking lost control over my body fell back onto the arm chair and because of my shaking I fell of the arm chair and on to the groin where I hit my head, I woke up with a  huge headache from falling and my brother described my movements like a seizure. Does anybody know what might be wrong with me pleas help .