Well, I recommend in general getting this book: http://www.amazon.com/Feeling-Good-The-Mood-Therapy/dp/03808... (the good basic, for "patients" vs. doctors book on cognitive therapy (now cognitive-behavioral therapy, but I read it before that addition), and take the Burns Depression Checklist at the beginning of chapter 2. Based on your score, you'll get a rough idea from "no depression", "normal but unhappy", then "mild depression" all the way to "extreme depression". Based on that you can then know appropriate steps to take.
I'd add that I'll bet anyone can benefit from going through their thought patterns applying the insights of congnitive psychology, the therapy side of which says, very roughly, one way to make yourself depressed is to think incorrect bad thoughts about yourself (which includes how you view other people viewing you, etc.).
(Which is not to say there aren't also pure biological causes (see tokenadult's excellent comment: https://news.ycombinator.com/item?id=7530847), family history eventually revealed that's a factor in my particular type of depression, but it's certain that self-applied cognitive therapy from an earlier edition of this book made a big difference for me, it's just not enough.)
I'd add that I'll bet anyone can benefit from going through their thought patterns applying the insights of congnitive psychology, the therapy side of which says, very roughly, one way to make yourself depressed is to think incorrect bad thoughts about yourself (which includes how you view other people viewing you, etc.).
(Which is not to say there aren't also pure biological causes (see tokenadult's excellent comment: https://news.ycombinator.com/item?id=7530847), family history eventually revealed that's a factor in my particular type of depression, but it's certain that self-applied cognitive therapy from an earlier edition of this book made a big difference for me, it's just not enough.)