What Will said.
However, I’d like to add…I go through a process when an uncomfortable emotion, which is the final product of our thoughts, is triggered.
Something along the following lines:
+What belief or thought must I have about a particular situation to produce that emotion?
+Is that a rational, logical and empowering thought or belief…or is it limiting?
+If not, what can I try and replace that belief with?

I’ll try an example….

My wife was late home from work and I couldn’t get away to my squash game on time…so I was spitting chips (to coin an Australian phrase)!
I believe my wife should make sure she is always on time for my appointments.
The reality is that she could get sidetracked or held back late at work or stuck in traffic…so I would be banging my head against a brick wall expecting her to always meet my requirements.
So, a more empowering belief or thought might be…I would prefer my wife to be on time, however, I understand that it’s not always possible and I’ll deal with that.

Very long winded…but I hope you get my point.
And finally…thank God…don’t be worried by thoughts of failing, because you WILL sometimes. That’s the way us humans work.Learn from it, adjust your beliefs and move on.