Why am I becoming more fatigued and less energetic lately?

50 year old male, but never have felt my age until now. For the past five years, have been working 60+ hours a week on my feet, eating once a day, usually in the morning. Sleep about 4 to 5 hours a night. Live in my car, by choice, not circumstance. Long story. Never have been bothered by lack of energy and fatigue until now. It is really debilitating. Any suggestions??