hey, im a 16 year old female and i keep getting dizzy when i stand up, and then my vision goes all black and blurry and them my head feels like it gets hotter and i have to hold on to something to make sure i dont fall over, i sometimes get a sensation that im moving and about to fall over although im standing still and leaning on something, and then im fine, this happens quite alot, so far today its happened 3 times, but sometimes it gets as bad as about 5 or 6 times a day depending on how much im moving, it doesnt happen everyday but quite regularly, i was just wondering if its something i should be concerned about?