emma82 – you have my sympathies, it is crap time of year for depression sufferers. I also seem to slide quickly into a deeper depression a couple of weeks just after the clocks go back, although this year it hasn’t been too bad so far, but early days.
I don’t have a light box, I probably should but have never got round to it, but other things I can suggest are
1/ Get outdoors irrespective of how cloudy. cold and miserable it is, even on the worst of days 30 mins of natural light can be helpful. A short walk at lunchtime maybe?
2/ Get your GP to check you vitamin D levels, I suspect we are all lacking at this time of year, but if you are prone to SAD low vitamin D will not make things any easier.
Gary