Simple = Hard
Simple things, to be sure. All you have to do to get over it is stop caring. All you have to do to calm down is stop being angry. All you have to win is be ahead of the other guy when time runs out.
Of course, it's not that easy. There's a ton of stuff you have to do to get ahead of that other guy before time runs out. There's a lot you have to get settled before you can stop caring.
It really is that simple. But it's usually the simple things that are the hardest to do. Never let anyone attempt to convince you otherwise. And if you really want to do those things, it's going to take work. You will not accomplish them without doing the work, period, point blank, end of story.
You can delude yourself into thinking otherwise. You can run. You can hide. But eventually you'll get caught. So instead of wasting that time, why not turn into the wave and ride it out?
It won't be easy. But it's that simple.