Andi, first, HAPPY BIRTHDAY!
Second, what would you tell any of us -- hell, you probably already HAVE told some of us, because you are unfailingly supportive and compassionate -- who work extremely hard at jobs we care about, if we said we felt guilty when we aren't at work?
My guess it is would be something like: you pour your generous heart and good soul into your job, and you do real good for a lot of people when you're there. But everyone deserves and needs downtime. You can't work 24/7. You need the downtime away from work and away from the concerns of work so that you don't get drained and burned out. Because if you get burned out, then you won't be able to do such good when you *are* at work.
You are not responsible for everything, and taking downtime and letting work go when you aren't at work is important self-care. That's what you'd tell us, so that's what I'm telling you. Be as good to you as you are to us.