Are you a musician or a composer? How well did your favorite composer play the cello? The violin? The French Horn? Probably not that well!
You are comparing your insides with the composer’s outside, his work. But you have no idea what personal internal struggles he or she had when writing it, unless it is one of the really famous composers, and then you realize they were mad, or obsessed, or unable to get it performed or a hundred other stories.
Oh, and feelings are never wrong. Feel them, and then ask why? And what would you do to feel differently? Then do that. If you need a constructive exercise, sit down and write ten things you are grateful for today. You can start with the fact you woke up today. It beats the alternative!