Got linked to
This superman comic again. And it clicked. This is exactly why, despite how depressed I've got, how anxious I've ever been, and how badly things go - I've never had a suicidal thought. No matter how bad it is at the moment in time, there's still a tiny part of me thinking logically and trying to remember the good times, and how all the other times I've fallen I've managed to get back on my feet.
I don't know if this'll help anyone else who's had/has similar issues. Was just a realisation that made me feel some sort of bittersweet happiness.