I view depression as being a logical response to existing in a world as hellish as this rather than an "illness". I would say that for the most part rather than worrying all the time about what lies ahead, I'm mostly just feeling tired of existing and wishing that I wasn't here. At least to me, it makes sense to wish to be free from something that is as useless and unnecessary as existence. I could never wish to suffer and life in itself is suffering. But of course all of the uncertainty involved in existence can certainly cause anxiety. It's terrifying how there is no limit as to how much we can be tortured in this world.