Since people seem to be sharing their favorite quotes, I'll share a couple of my own. It's kind of like a litany to repeat in difficult situations, replace placeholders as needed:
“What is true is already so. Owning up to it doesn't make it worse. Not being open about it doesn't make it go away. And because it's true, it is what is there to be interacted with. Anything untrue isn't there to be lived. People can stand what is true, for they are already enduring it."
"If [scary thought] is true, I want to believe that. If [scary thought] is not true, I want not to believe [scary thought]. Let me not become attached to beliefs I may not want. If I'm living in a world where [scary thought] is true, that’s what I have to believe, I have to know what’s coming, so I can stop it, or in the very worst case, be prepared to do what I can in the time I have left. Not believing it won’t stop it from happening."
"I am not afraid. I am not afraid because if I let myself get too scared I might not be able to do what needs to be done. And I'm not the type of person who backs down. I am the type of person who does the right thing, even if it's hard. Right now, the right thing is to [x]. And even if it doesn't work, I'll just do the next right thing, and the next, and the next. I'll keep on trying until I figure out a way."
“What is true is already so. Owning up to it doesn't make it worse. Not being open about it doesn't make it go away. And because it's true, it is what is there to be interacted with. Anything untrue isn't there to be lived. People can stand what is true, for they are already enduring it."
"If [scary thought] is true, I want to believe that. If [scary thought] is not true, I want not to believe [scary thought]. Let me not become attached to beliefs I may not want. If I'm living in a world where [scary thought] is true, that’s what I have to believe, I have to know what’s coming, so I can stop it, or in the very worst case, be prepared to do what I can in the time I have left. Not believing it won’t stop it from happening."
"I am not afraid. I am not afraid because if I let myself get too scared I might not be able to do what needs to be done. And I'm not the type of person who backs down. I am the type of person who does the right thing, even if it's hard. Right now, the right thing is to [x]. And even if it doesn't work, I'll just do the next right thing, and the next, and the next. I'll keep on trying until I figure out a way."