Its called Seasonal Affective Disorder. They reckon the full blown variant affects 7% of the UK population every year over Winter (November to March ish), but up to 17% of people on top of the 7% suffer mild symptoms, and its pretty much exactly whats been detailed here:
Down and depressed
Less interested in doing things or delaying doing things
Loss of libido
Over eating
Waking up in the night
Waking up too early
More tired than usual, heavy limbs, aching muscles or headaches
Stomach problems, sweating, cramps, having to urinate frequently, dry mouth, sighing, heart palpitations, hyperventilating
Feeling tense, irritable, worrying too much about little things
Thoughts or speech are slow
Fidgety, restless, hard to concentrate
Paranoid and suspicious
Allegedly (although I suffer mildly I haven't tried the treatment yet), these:
http://www.maplin.co.uk/sad-light-box-226759 help greatly.