S.A.D or just sad?

I spent the first 21 years of my life in the UK and longed for the sun and warmth of Italy and Southern France once I was old enough to escape. I married an Aussie and spent 12 years suffering the cold of Melbourne winters until we moved to Queensland.
Here on the Sunshine Coast I thawed most of the year but once the temperature gets below 25 my misery returns. I just cannot tolerate cold weather and my personality becomes affected. Usually I am an outgoing, active, full of fun individual but when the temperature drops I try to avoid people because they notice I am depressed, usually hacking away with a chest infection and no fun at all. For years I was told I am just miserable but then my respiratory specialist told me I suffer a genuine medical condition called Seasonal Adjustment Disorder. It particularly affects people living in cold climates such as Scandinavia, Canada and Russia. Thank Heavens I live in Queensland so it only lasts a few weeks. At least knowing I suffer S.A.D and am not just sad gives me a warm feeling. Does anyone else suffer this condition?