Me and My Shadow

I'm curious about my shadow in the sun it follows me around, but if I move into the shade my shadow's nowhere to be found. Did light create something dark or is this a part of me, maybe it's just my negative something I don't often see. I suppose it could be my dark side being separated by the sun, in the sunshine I do feel much happier and I do tend to have more fun. It follows my every movement just can't make a move alone, but if I stand still long enough my shadow will move on it's own.