Many of us suffer from Seasonal Affective Disorder (SAD). I actually suffer from unipolar depression with season attributes. In other words, things get worse in the winter. This article is quite good and talks about things to improve the situation. I find the lightbox helps about 10-20%. If you are really having problems, then see your GP, and ask for a referral to a psychiatrist, who can give you some simple pills. These pills are actually healthy, since they beef up vital nutrients to the brain, and regrow some sections.