I am a bit concerned with my future health. A couple of weeks ago I had a 102 degree fever that took me four days to recover. During the process of recovery I experience the typical light headedness, but every single time I stood up, I blacked out, lost total vision for 10 seconds (approx.), got a terrible migraine attack, and was forced to grab hold of something. I wasn't too concerned because I knew that I was sick and that I needed to rest and that it would all go away. I also thought that maybe I was dehydrated, but I was way to parched during my sickness to deal with anything, so I was always well hydrated and had perfectly colored urine (straw colored.) Even though I haven't had a fever in almost 2 1/2 weeks, I have the exact same symptom even though my urine has been really healthy the whole time. I still have to grab hold of something, I get a head ache, and I become completely blind for up to 10 seconds. I even exercise frequently and my blood flow should be fine, but even if I sit down for 5 mins or and hour, the same thing ends up happening. What's wrong?