If you are legit worried about it, then it's probably time to take, like, an inch more breathing room than you are now. No project you are working on is worth your life and health. If a friend of yours was in that position, you would not want them working so hard they hurt.
I can't argue you into caring about yourself. Please try to keep it in mind though, especially if you think of it as an attitude where you would probably be very concerned if you heard another person you cared for was approaching a project this way.