Pud, I have suffered with SAD for many years. However there are two things that have helped.
Getting outside in the middle of the day, particularly the cold bright days, helps - I walk the dog then and exercise is beneficial with SAD.
I purchased a special SAD lamp- simulates day light. If you sit beside/infront of it for about 1 hour a day it can really help. If you are out at work, some people take them to work with them and have them on their desk. I find it best when I sit and eat breakfast. Helps to wake me up and get going, although any time up to early afternoon is good. Don't use it too late though as it can upset your sleep routine. Not cheap, but I have had mine about 10 years and it is still going strong with 1st bulb.
