We're not so different in age, and I'd be lying if I said I never feel the way you describe. However, these are some things that helped me, in increasing order of importance:

- Health. Covered already, but I'd add that you don't need to be in marathon shape. Just hit the basics: sleep, exercise (walking is enough!), diet. It's easy to feel things are ok in any of these dimensions but actually be out of whack.

- Do things with your hands. Humans develop insofar was they learn to manipulate the physical environment around them. This is one of the tenets of the Montessori pedagogy, but I found that it doesn't just apply to kids! I feel _great_ when I install a toilet, paint my living room, fix the car. There's just something about physically doing stuff with your hands.

- This one is hard to describe...I took inventory of my 'philosophical operating system' and realized that I was organizing my life around something without legs. In my 20's I was heavily influenced by stuff like '4-hour-workweek' (lol), the gary-vees, the pg essays, etc. It's not jut practical advice...it's a philosophical system and worldview. When I looked under the hood, it was all spaghetti code. It couldn't stand up to more cogent and complete philosophies, which I found literally down the street.