Depression is usually triggered by negative thinking. If you try to change the way you think by replacing those malicious thoughts with the new ones that are positive, you will be surprised. You depression could just vanish!
Peoplw who suffer from dwpression subcontiously change their cognitive style, or the way they think. They tend to think negatively, think that something wrong is going to happen if they do this or that! This fact bring us to the consequences that it may induce. The usual outcome of negative cognitive style is bad mood, wrong perception and changed behavior.
First thing that you should do when you notice these changes is to make an effort in changing your negative thoughts. You can think that you are responsible for something, or that you will never do anything right or anything else that is negative. These thoughts can be verry variable, but they should be recognized because they are allways negative.
To recognize them you can try to write down everything and I mean everything that crosses your mind. By doing that you can read them carefuly and notice those ones that are making you feel bad. The thoughts that are the most harmfull are those ones that are in the terms all or nothing. That means that something is just good or bad and there is nothing in between, which is of course wrong! Also, do not take things too personally because not everything is done for you to be provoked.
The best thing you can do if you recognize signs of depression is to talk to your therapist. Studies showed that cognitive-behaivoral therapy or CBT is verry effective when it comes to resolving problems with negative thinking.
You should find a good CBT therapist and help yourself to enjoy life!