(No, I'm not pregnant!)
Why am I so down lately? Maybe it's the weather, or stress?
Answers: Many people acquire down during the winter months. It's called Seasonal Affective Disorder (acronym: SAD). It's related to standard lamp; in reality, there is a special night light you can put in your house to abet you.
Also, if you've gone through a particularly stressful time just now, that could be affecting you.
Going on a run helps, or anything kind of exercise you prefer. Something to put together you feel close to you're not all "cooped up".
I hope you bring out of the dumps!