So it's easy to get stage-fright here and start to feel a little bad about your performance -- it's a totally healthy reaction.
However, don't get bogged down, but always analyze how you arrived at the failure and if in doubt, listen to Zappa:
Finally, remember, your mistakes currently are simple ones. As you get better, your mistakes will get more sophisticated, and you'll end up thinking fondly of the time when a white space or a simple procedural error was your biggest problem. So, enjoy this happy time whilst it lasts :)