Also, a hack I learned from Kristina Kuzmic: use "right now".
Whenever you're thinking of something shitty, like bills coming in or just feeling that life sucks, it helps a ton to add "right now" at the end of it.
It's a small reminder that the misery is temporary as opposed to giving it a permanent dimension.
Don't just say I feel shitty, say I feel shitty right now.
That too shall pass.