I know the feeling about being very busy. I have worked at jobs where people work 12 hours a day six days a week. It wore me out, but many loved the overtime. I preferred having some time off to actually rest. I tried to get my hours cut, but they still put me on the schedule for six days a week. I eventually had to leave for a medical reason, but it did take its toll.
Going outside for a brief breathe of fresh air is a great idea. I loved jobs where I could get outside, and frequently would volunteer for them.
Your health is too important to you so slow down if need be. If you are in the hospital, the supervisors are given a choice of keeping it for you or doing it themselves.