I'm so sorry to hear about your continual sadness. I know how much it sucks to be sad all the time - I cycle in and out of periods of sadness. Just know that there is a light at the end of the tunnel, and there are many different ways to get there.
I think it's great that you've found music as a form of coming to terms with your feelings. As a singer/songwriter myself, I've always said that music is a kind of therapy for me. It's true, music helps you connect with feelings that you didn't know you had, or can't put into words easily.
It may be worth having a chat to a psychologist or a therapist and seeing what they recommend. Otherwise, we're always here to have a casual chat with you if there's something else you'd like to get off your chest :)
Thank you so much for sharing your experience, I wish you all the best.