Of course you have to deal with the source of your depression. If can laugh at yourself for making too much out of something trivial, then you've achieved a necessary distance from your problems. That in turn will give you energy and perspective to deal with the more serious underlying cause. Each day should be fresh. Don't come with preconceived notions.
Laughter helps clear the air.
So break out of it and have a laugh. Be creative in the world that is made for us, for our challenge and that is our opportunity. Don't pity yourself. Because laughter is a subconscious release of tension. So use laughter consciously to break tension in yourself and others.