Hello Embodiment: I noticed this is your first post here on PC. So... welcome to PsychCentral.

There is a type of depression that is referred to as "existential depression". Perhaps you're familiar with the concept? Here are links to some articles, from PsychCentral's archives on the subject:

What is Existential Depression?

Coping with Existential Depression

Existential Despair: A Deeper Cause of Human Anxiety

15 Existential Questions that Could Improve Mental Health | NLP Discoveries

Ducking Existential Questions Linked To Mental Health Issues

I hope you find PC to be of benefit.