Hi, I'm 16 and I've been feeling like I'm going faint or blackout when i stand or walk for long periods of time. recently while i was walking i came to a point where my body felt like it was going to shut down i was literally walking like a zombie, i told my mom i felt like i was dying. My body had got so weak. Another incident was when I was standing on line for a long time and my body shut down, it was terrible, i got so lightheaded, i felt as if i was going to blackout. Swaying/moving helped.