This resonated a lot with me. I am also addicted to being useful and find that off days where my output and usefulness isn't where I'd like it to be really tank my self esteem.

I do think it can be a double-edged sword that often leads to burnout. Respecting your limits and occasional therapy seem to help, as does ensuring you're in as stable and supportive environment as possible so your efforts are sustainable and "heroics" don't get normalized in your org. I wish I had a full solution but have yet to find one in my career that works :)