Look up "failure" on the internet and you will find a wide range of examples of failure. Wikipedia makes a point of emphasizing that "the degree of success or failure in a situation may be differently viewed by distinct observers or participants, such that a situation that one considers to be a failure, another might consider to be a success, a qualified success or a neutral situation."
So really, when you're looking at yourself and saying that you did not reach your goal, which makes you a failure, it's important to realize that not everyone is going to look at your situation in the same way.
So, what is the best way to approach what you define as failure? Acknowledge that there was a gap between where you wanted to go and where you ended up. Determine where the problem stems from: the goal, the effort... OR things beyond your control like timing or luck? If your goal is untenable given your present situation, not adjusting it will kill your self-confidence in the long run and ruin your chances of success EVER. If your effort is misplaced, you are exerting too much in the wrong direction - not adjusting your approach will waste more time. If timing or luck messed up your end result but your goal and approach were on track, just keep doing what you're doing - DON'T GIVE UP!
Only when you are able to get beyond failure will you be truly able to enjoy your successes and build upon them. Don't be too hard on yourself - sometimes you have to give yourself a break in order to perform your best.
