I'm way too sedentary, so physical fatigue is rarely a problem. I'm not particularly emotional or empathetic either--more my temperament than my preference.
I've been through depression, so that's the one I most relate to. I've heard that depression is like frostbite. Once you've had it, you're more vulnerable to experiencing a repeat of it. I had a major one between 1989 and 1991, then a relapse in 2003 that only lasted a few months. Every so often, I recognize the "depression fatigue" symptoms you listed.
I've never been in the position of being someone's caregiver, but that could change. I'm good at setting boundaries, and I know the value of self-care. I hope these skills will keep me sane if I ever have to take on that role.
I'm retired and have sufficient income for my needs. I'm not ambitious, so future fatigue isn't a problem either. I live in the present and don't get anxious about what I have no control over.
I am so grateful for the healing God has done in my life since my 30s through the Eucharist, 12-step programs, therapy, and spiritual direction. I'm no longer codependent, and I'm able to see myself as I know Jesus and my heavenly Father see me.