Yep, I have had the light headedness and mild headaches a few times, once after Ministry of Sound, and right now following Digital. I can't be sure, but I think it's because I end up catching some kind of virus or something due to a run down immune system from the hours of partying. Last time it ended with quite a harsh fever that was gone overnight. This time it's nothing much at all, just feel dizzy a lot. But two of my friends who went along to Digital got really sick with a flu on Tuesday - better now though.
Just have to take care of yourself once you get home - eat properly, plenty of sleep and rest etc. Maybe try to not share drink bottles at parties? Anyhow, best of luck getting over it!
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Life is best described by this question:
"Is there anyone aboard who knows how to fly the plane?"