You've been working too many hours for too long. It's time for a break.
You may be thinking that there's no way you could take a break. Your work is too important, or you think you're too important. Maybe both of those are true. If so, you're doing your work and self a disservice by not taking time off.
Time off will clear your mind, give you perspective, and get you some much needed sleep.
It's ok to take a break for a while. Everything will be fine when you get back.