Self-esteem and self-confidence are two different things, although both usually go side by side in defining a person. Self-esteem means confidence in one's own worth. One's self-worth, self-respect, self-pride, self-belief, are different words that can be used to define someone's self-esteem.
It simply means how you value yourself; your own opinion about yourself. Self-esteem is built when you start having certain notions and opinions about our abilities. On the other hand, self-confidence is a measure of your belief in your own abilities. This is usually a reflection of someone's state of mind when you can conveniently rely on your own abilities.
When you are self-confident, you no longer see any impossibility in the things you can do. It creates a feeling in you that keeps assuring you that you can succeed in almost anything. In short, self-esteem is a measure of how much you love yourself regardless of anything, while self-confidence is a measure of your trust in your abilities.