If you spend your time hoping someone will suffer the consequences for what they did to your heart, then you're allowing them to hurt you a second time in your mind.
To be rejected by someone doesn't mean you should also reject yourself or that you should think of yourself as a lesser person. It doesn't mean that nobody will ever love you anymore. Remember that only ONE person has rejected you at the moment, and it only hurt so much because to you, that person's opinion symbolized the opinion of the whole world, of God.