Reddit reviews Positive Disintegration

Here's what helped me:

The Existentialists Survival Guide

Positive Disintegration

They're not 'cure all solutions,' but after dealing with this for about 7 years, it gave me a better understanding and perspective on my life. I feel like this happens to a lot of people who are just beginning to consciously construct their own identity after either being forcefully made to (e.g., divorce, job loss) or after years of general stagnation. Read Positive Disintegration for more in this, it was eye-opening for me - I even went back to school at 35 to pursue my degree in psychology.

Finding a social circle with people who understand and/or feel the same way (like here) has also helped. Try a whole bunch of different things (e.g., painting, woodworking, studying biology) and see if anything peaks your interest, if not, move on to something different. When we get knocked off a track, or we realize the track we've been on all of lives is the wrong one, it can be scary because we feel like we're don't know who we are now. Instead try to look at it like a blank canvas and we're free to be the person that we want to be according to our beliefs and values. Good vibes my friend.