Believe in yourself! Have faith in your abilities! Without a humble but reasonable confidence in your own powers you cannot be successful or happy.
If we refuse to believe in ourselves, we simply refuse to live a great life. Success in life is determined greatly by the amount of value we are willing to place in our own thoughts, and our everyday actions.
Once you are able to believe that life is important, and that the decisions you make daily do very much matter, you will notice a considerable change from the life you once lived.
So effectively, we have a limitless life available to us if we really desire it. If we just live knowing that what we have already is enough. If we live a life believing that each move we make can be a step forward, no matter what comes our way, we will be champions in life! So love yourself, believe in yourself, and from this you will see success and happiness as a recurring theme in your life. Don't worry or stress, love life and be happy!