Whenever i am laying down for a long period of time, as soon as i stand up i get extremely dizzy and i get a ringing in my ear and i fall on to my bed and have to just lay there for about a minute then when i get up to recover i have a splitting head ache. My parents don't trust me that something could actually be wrong. I work out about 5 days a week and i drink lots of water but these fainting spells happen just about everyday sometimes twice a day. What could be wrong with me?