I can so relate. The mistakes. The regrets. The guilt. The anxiety. The sleep disorders. I've got it all in spades.
I don't know what to tell you? I'm working on it myself. Sometimes I think of people who stepped in and helped me through difficult times in my life, and then I try to pay it forward even in small ways to other people I meet who are themselves in a bad place. I find this therapeutic.
I suppose on the bright side, my past has made me a humble person who is not quick to judge others. But there's a fragility there too, and I fear for how I would cope with whatever new challenges await. These are rather uncertain times.
Maybe you can take some comfort in knowing you're not the only one in this funk? I think you've actually made me feel better about it a little bit. Anyway, best of luck to you that you find your way.