"Burn-Out"

I am about to "burn-out" from my current job. All summer I have had two full timers off due to injuries. I have averaged 60-70 hours a week and am tired. When I started back to school, 1 of them came back, easing the situation some but not much. This person has decided that he "doesn't want to work any O-T" and has put in his resignation...effective immediately. I am having trouble "juggling" my time between school/work/home. I have 185 hours of sick time,160+ hours of vacation but, vacations are "frozen" due to lack of personnel. As manager, would it be "ethical" to come down with the "blue-flu"? Or, should I just put in my resignation also? I have been there 3+ years and USED to enjoy going to work. <SIGH> I am getting tired.