I do prefer overcast days too. I think for me I have enough English blood that the entire lack of sunlight thing doesn't effect me in a negative depressy way, and I know overcast days have a way of milding out the temperature so an overcast day in the summer is cooler while an overcast day in the winter is warmer. I also really really hate heat.

That being said, yeh, if a dislike of sunlight is more than just grumbling and fatigue then you might want to see someone.