My dad is bipolar and has suffered from depression, addictions, and many other issues for many many years, most of his life. He often thought of suicide. These things are very serious and are not to be taken lightly. If you are thinking of suicide, or have thought about it, even if you "talked yourself out of it" (as my dad put it), there's something not quite right. That's not something to ignore.
My dad also has seasonal mood disorder. In the winter months, when it's dark and cold and ugly out, he goes into depression, which brings up other issues, spending money, lack of sleep, etc. It's because you aren't getting enough natural light. The sun provides vitamins to your body and it naturally makes you feel happier and more energized. So when that is lacking, especially with someone who suffers from depression, it can make you feel really awful. And not only mentally, but physically too. Taking vitamins, eating healthy, drinking lots of water, exercising, and getting as much light as possible can really help alot. And it doesn't help just with seasonal depression, but for anyone.
My family and I have gone through ALOT with my dad. And these issues aren't something that I take lightly. It can be very serious. I mean, my dad was diagnosed improperly by one doctor and given medication that only worsens bipolar disorder. He went for second and third opinions and they all came to the conclusion after LOTS of testing and councelling that my dad has been this way his WHOLE life. He was not diagnosed properly until he was... 30 something. If it had been treated earlier, he may not have had to live through some of the pain he went/is going through. He may not have made some stupid decisions. Who knows. But if you or ANYONE you know is contemplating suicide, please get help. Talk to someone professionally.
Just my little story... but that's all I have to say for now.