True self-confidence is being able to be confident about being just the way you are. Take pleasure into your own thoughts and your own life. If you live your life expecting validation from others, you will often get disappointed. Love yourself.
Most people think they need to overcompensate on their weaknesses like say, going from extremely shy to becoming an arrogant extrovert. The latter represents someone who is trying to be better than everybody else.
You want to be somewhere in the middle.
And if a pretty girl says: "get lost, you creep!" take heart that you at least got a reaction from her

Then just move on.