Just been diagnosed with sad

Hi Gem,
Welcome to the forum, and sorry you're feeling so low. Yes, there are a lot of lightboxes on the market! The type to look for is one that emits 10,000 lux, as you will get most benefit from this strength. I bought a LitePod, if that's any help, and have always been very happy (excuse the pun!) with it.
The first winter I had SAD, it wasn't diagnosed, and I had counselling,but it didn't really help. Anti-depressants did the trick, although rather slowly, on that occasion. It was diagnosed in the third winter, and the lightbox made all the difference (although I was sceptical before that).
In the end, what you find most helpful might be therapy, or a lightbox, or antidepressants, or a combination of these, so it might be best to go ahead and try whatever your doctor is suggesting. That way, you will find what helps you, individually, most.
For helping partners understand SAD,as I mentioned in another thread,I gave my OH "Seasonal Affective Disorder for Dummies" to read, which helped a lot.
Good luck, and let us know how you get on.