In the spirit of the Olympics, I have to make a short concise statement. World-class athletes can have an off day. The difference between the winner and everyone else is oft times shaking off disappointment and errors, focusing on their goal. You can do the same, if you have a bad day or week, just focus on your goal!
The best gymnast in the world did not make it to the all-around competition because of minor errors, so if the worlds best can have an off day or miss their mark, there is nothing wrong with you having similar results. Just move on! The past is the past, that was yesterday, now only today matters!