Everyone experiences moods with various degrees of relative ups and downs.
People who think they are depressed are people who hold their low moods in place with their thinking. If you think you are depressed and allow for the possibility that you might feel better, then you probably will, and that will prove that your mood fluctuates just like every other innately healthy human being.
If you ever feel in a low mood, you don't need to do anything about it - low moods will pass of their own accord if you accept them and allow them to, and allowing your mind to quieten will often lead to more feelings of calm and wise insights arising.
Your thoughts create your feelings, and if you feel down, or up, you just need to realise that your current feelings were created what you were and are thinking. When you let go of the thinking that created your feelings, what you are feeling will pass naturally.
You don't have control over the thoughts that appear in your mind, and you don't need to analyse your thinking in an attempt to fix your moods. When you recognize and understand that the thoughts you have created the way you feel, you can regain present moment awareness with a renewed sense of your innate wellbeing. And that can make music sound really beautiful, too. 
Edited by Windsor - 9/23/11 at 6:41pm