Depression is much more common than people acknowledge. It is not just with people that are clinically depressed or diagnosed. We all go though emotional cycles and can get down at times. January is a common time for this.
Feelings are a call to action. If I am feeling sad, lonely, or unfulfilled, it is a signal that I should attend to that area of my life.
Also, the best way to work through a depression is to take action. As soon as you engage in a project, activity, or relationship, you are not depressed anymore. Of course, the last thing that you feel like doing when you are feeling down is taking action. Usually, you have to force yourself. Sitting at home and feeling sorry for yourself may feel good (it releases endorphins), but it is not effective to work through the blahs.
So take that class, start that art project, get out and socialize. Make plans. Find something to look forward to. Flirt. Ask somebody out. Orchestrate a romantic evening with your significant other. Remember, it is a good time to position yourself for another emotionally-laden holiday around the corner- Valentine's Day.
So Happy January! What can you look forward to?