Thank you all so much for your replies- they've been very helpful. I think it also just helps to know that other people have gone through/are going through the same thing. I'll definitely give St. John's Wort a go I think. It seems quite easy to get hold of too, which is a plus! The points about keeping hydrated and vitamin B12 hadn't occurred to me at all, strange how the little things can be so important. I really like the idea of a diary as well- I'm usually pretty lazy about things like that, but it'd just take a little effort.
As for the flower remedies, I'm trying Larch at the moment. Although they seem quite a strange concept to me, I'm keeping an open mind about them for the time being.
Unfortunately, sunshine is the one thing I can't get hold of! (daylight seems to be a rarity here in the midlands!) I have been considering buying a lightbox for a while, but they're quite pricey, so will have to wait till the student loan comes in in January. (Thank goodness for loans!) Having looked into it, they sound pretty effective. It's reassuring to hear that some of you think so as well.
Although the antidepressants are effective (and if things start to get bad I wouldn't object to taking them again), and I do trust my doctor's advice, there's always the trouble of side effects (nausea and eccessive sweating, yuk!), and I really don't enjoy coming off them. I think I can relate to what you're saying Lynne, in that I don't think they'll be a positive thing for me to be on in the long run. It won't go away overnight, and I'd like to have some long-term strategies outside of medication. (So all of your suggestions come into this

) I'm aiming to introduce a new one every week or so, hopefully there'll be some good results. I'm feeling hopeful, which is a good start!
Many thanks,
Bryony