Sitting at desk is depressing me.

Iv been either in the military or a construction worker my whole life. Outside all day everyday, meeting people and working out. I started my own business 4 years ago at 42 it's growing fast. Due to the administrative load and bad joints I'm in the office all day now and have for the last 2 months. My crew is more than capable and also don't need me in the field.

I can't afford an office person yet so I'm kind of stuck in here. I'm feeling depressed even though my business is doing well. Any advice?