People often wonder about depression. They wonder what causes it and if it is something they've done. In reality, Depression is the even uglier sister (or brother) of Anxiety. Anxiety leads to depression. Worry; fear; uncertainty; selfl-loathing thoughts---can lead to depression.
Depression is a serious reaction to Anxiety. When the Anxiety leads to hopeless and sad thoughts, fear and despair grip our thoughts. Sometimes treating your anxiety can eliminate your depression.
Retraining your thoughts to allay internal fears can be very helpful and, in cases where you can't seem to get it under control on your own, there are antidepressants out there that can help. They work not as much on the sadness as they restore your natural levels of Serotonin, which makes the brain feel more at east with life.
Don't let the hidden ugliness of Depression pull you under. Seek help, right away. Then, consider that you may be wringing yoru hands or bouncing your leg in a relief of Anxiety and consider what gettting that Anxiety under control could do for you.