From a rational standpoint, I don't have faith. No gods, no afterlife, no wishful thinking, prayers or things of that sort. Life's now and once I'm dead, that's it (thankfully).
I may have a day-to-day faith: that tomorrow I will wake up in the same city and that a nuclear bomb hasn't been detonated above our heads, that a spectacularly fast meteorite completely made of undetectable matter won't hit the Earth while I sleep (or something to that effect).
I guess the only thing I have to believe from time to time is that I'll get better. There are times in which I really see everything black and everything I do and live through loses sense. I don't really know why this happens or how does it develop; I'm just glad it's not lasting as long as it used to do just some months ago. And probably it doesn't last as much because I believe it is a transient state.
I do have my schedule fairly arranged, and try to keep on doing that regularly. It's about keeping contact with different people, getting engaged in different activities, arrange to go to the theatre, play sports or whatever thing, during the next week at least.
That's my mechanism of self-defence against myself. I spin the wheel hard when I can, and when I'm at the bottom of the pit, somehow the wheel keeps on going for a while.
The axis on which the wheel spins is that belief that my mood will get better.