I’ve had terrible existential anxiety since I was 9, what books settled your existential or life/death fears?

It's funny I genuinely think I remember the first time I pushed things too far and triggered my existential anxiety. I was raised Baptist evangelical so I'd been in church every Sunday since I could remember but one day I remember I was sitting in the front row, no more than 9. It finally struck me that I didn't really care about heaven or hell it was the concept of eternity that terrified me more than anything. Sometimes I end up thinking back as if this specific incident didn't happen I wouldn't be as scared as I was.

I'm an adult now. I haven't been Christian since I was 12, I have some spiritual beliefs but nothing around death or afterlife. The thing is genuinely I didn't stop being religious out of fear it kind of just slid off me, never taking root. It was all just lip service but I didn't realize that until a certain age. But I am still terrified by the idea of non-existence (and eternal existence!) and the scale of time. Questioning if anything is real. Not really in a psychosis way though, at least not that my therapist thinks.

Anyways I'm rambling. Basically I'm interested to hear books that comforted or soothed fears like these, or maybe one that kind of just stun you into silence. Very vague I know. I guess to maybe get across the feeling I mean, it's something I felt after reading stone butch blues the first time. Contemplative maybe. Wether it's someone's memoir or a fiction story or a more abstract book of poems. I enjoy all sorts of art. Not looking for any specific religious guides.

Hopefully this is enough description <:)