I started working the overnight shift about 3 months ago and after about a month I started to feel a lot more fatigued and sad than I normally am. It obviously has something to do with my change in routine, since nothing else in my life has really changed and nothing bad has happened. I sleep Ok in the daytime but I never wake up feeling refreshed. Do you think one of those really strong lights people use for winter depression might help me, since I never really see much daylight? I think it might fix my problem but I do not want to buy one since they are expensive unless it is likely to work.
It sounds like you're pretty sure this is worth trying. I can't tell you whether or not it is going to work for you. Some people have told me that these lights helped alleviate their feelings of depression. I don't know anyone who has used it in your situation, but it makes sense that it could help.
If you're worried about the cost maybe you can borrow one from someone, or try one out on a sale or return basis? If not you need to consider whether the chance of improving your sleep and wellbeing are worth the risk of wasting some money.
I wish you well and hope you find a way of improving how you feel.