My girlfriend thinks my mental exhaustion comes from the fact that I am very introverted and quiet, but at work I'm in charge of 30 employees. That forces me to "wear" a personality that isn't my own. I really want to change fields altogether, but at 35 I feel like I'm on borrowed time and should already be properly nested in my career.
That's your parents' generation talking. Go find you a nice computer job where at most you have to deal with your co-workers at most an hour a day.
I speak from experience. My father was 14 years into his 21 total with the Air Force by my age. I've tried comparing myself to him, and it just doesn't work. The economy isn't set up for 20 and a gold watch. Modern expectations that I've seen are that the average worker is expected to change careers 7 times during their working years. Given how "stable" economies are these days, I can believe it.
I am on my second industry as a computer programmer. I spent 11 years in the call centers, 3 of which as a Manager, at two different companies. I am introverted like you, and managing employees was a mental drain. Now that I'm a programmer, and a single one at that, I find that I have to work to get what little social interaction that I do need.
Yeah, my girlfriend keeps telling me to get out of the field, and go into computers, psychology, consulting, etc. I'm great working with people one-on-one or in small groups, but as the numbers increase so does my stress level. The strange thing is, in my reviews I'm rated as the most "mentoring and approachable" manager. I really, really
have a desire to go into police work after going with a friend on a few ride-alongs. I love helping people and he spends alot of time doing exactly that. Unfortunately, I'm at that age where departments probably won't look at me.