I wish I was as disciplined as you. One thing that helps me is to meet with my sometime-music-partner. Even working on some rando side project keeps the juices flowing. What I wish I had was a peer group to be accountable to, and to get feedback on my composition.
You have motivated me to set a timer to actually leave my house for a walk tomorrow. I've been spending 9 hours a day at my computer. It can't be good for me.