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.