Ugh hi beale, I am suffering already and I know there's some others on here too. Not much you can do really, try getting lots of vitamin C as well as a good night's sleep. GEt out in the fresh air, particularly if it's a sunny day.
Do you have a light box? If not may be wirth investing in one, I don't have one but i do have the sunclock which mimics the sun rise in the morning and is a great way to wake up.
As i said in a qeustion earlier about this I also have a sunbed every couple of weeks, I know that these are said to be very bad for you, but the boost I get from three minutes of light is brilliant, and i don't have them every day or anything.
I have also booked a holiday for november - when i get really bad, so instead of having a summer holiday i go then to help boost my sunlevels.
Until the doctor can prescribe me moving to california these are just the small tips to help cope in the winter months. Try www.outsidein.co.uk for more on light boxes, or www.sada.org.uk for more on SAD.