Exnihilio is dead on, get in or get out.
To get your head right, it might be useful to ask yourself - "What would Wanderlei do in this situation"? and if you think he would go for it, ask yourself - "What beliefs about himself and what actions would he take to prepare himself?".
Acting as if, fake it till you make it, if you will, by internally and externally modeling an idol is a very effective psychological tactic to employ, try to adopt his mindset and use of physiology to prep yourself.
People generally believe that Emotion drives Action, and often fail to realize that the opposite is also true, actions with control of your physiology with selftalk/visualization can retune emotion.It's usually much easier the latter than the former.
When I'm in a funk, fear is taking hold, I start by strongly saying outloud things like "**** this, bah, this ain't nothing, I can do it, etc, and accompany that with very bold crisp use of my body, then I incorporate my logical analytical side to make a plan of action and boldly carry it out, drive that anxiety/fear/ worry away.
Like anything else, the more you practice this, the easier and more powerful it becomes, try it, it absolutley works, you don't have to believe at first, the change of action will change your beliefs.