For me it was probably more that everything seemed meaningless, so why put effort in. Looking back I realized that it was also the first time in my life I didn’t feel like I could remake myself into a new career or big life change if I wanted to. Kinda stuck with the life I had, and even though that life was awesome it felt like less sense of adventure. By 51-52ish I was out of it and now think this phase of life with grown kids is awesome. Less figuring out what’s next, and more enjoying each day for the blessings it has.