I was Dxed w/ having SAD (seasonal affective disorder) about 4 years ago...and just like clockwork, when this Fall started closing in, so did the looming depression, not wanting to get out of bed on dreary days, etc. Sounds like you can relate. But I got an RX from my pdoc & there is a place in my city where you can go & if you have the right insurance, it's totally covered.
Light therapy is one the most prescribed and proven 100% effective for people w/ SAD. If you're really pressed for a light box, there are ones that you can get at WalMart that have enough UV to work. It helps if you spend a lot of time one the computer like I do, it helps to attach it to something above your PC. (it helps you to make less typo's too! )

The Poohbah has got the exact UV info above, but like I said they have some pretty darn good ones w/ high enough UV at WalMart that are quite cheap!

Good Luck & (((((((hugs!))))))))