Yes, I partially agree to your statements. Almost any creative endeavor requires a kind of emotional content. Even mundane tasks become easier and joyful to a happy person. It is truly a gift to be someone who can find joy in anything, and therefore be great at anything they do (even sweeping the floor with profound joy is supreme).

I find myself in a similar situation. I go through bouts of depression. Although I am much better now than I was a few months ago, I still go through cycles. Some days I feel calm and collected, and ready to start the day. Others I feel no motivation and don’t want to move. I notice that on days when I wake up happier my work progresses more smoothly and intelligently than on days when I’m depressed.

There is no reason why you can’t take breaks in what you do. You can still take up composing later in life once you become more stable. Try to find something else that gives you joy. Depression feeds on the feeling of restlessness and sloth. When you have a strong motivation, or purpose, then you can more easily cope. Do not give up everything just because you are going through a rough time. Do something else, and things will pass.