Never read a self-help book, I always assumed the authors were charlatans.

In my 50s I finally admitted to suffering from depression. I went through CBT, which felt oddly familiar until I realised that a lot of it was similar to Stoicism (I had read Epictetus and Marcus Aurelius some years previously). But sorting out what was me thinking and what was my brain chemistry acting up was very useful. CBT I would recommend. I would also recommend the Stoics and theTao te King. Also, oddly enough, Dune, especially the Litany Against Fear, which actually works, becuase it makes you stop and think, rather than panicking.

Talking therapy, which I took twice (thanks, NHS) was also useful, especially after my parents died. I was worried by my lack of grief. Now I construct narratives - even as a child, I never played for the sake of play, I always wanted my games to tell a story- and the therapy helped me create a connected narrative of my life. That allowed me to look at it and see how I got from there to here and how that explained the way I felt.

Overall, I would say that rather than rely on self-help, get some help!