Every time i stand up i'm so dizzy and my legs feel like there going to give out...

Ortho Hypotension: It sounds like you have orthostatic hypotension. Your blood pressure falls abnormally when you stand up. This is sometimes caused by something as simple as dehydration but can also be a sign of adrenal insufficiency or other autonomic nervous system disorders. This is treatable. You would benefit from an evaluation by a health care professional who can take your blood pressure and diagnose you.