Darkness,
You are good enough, and when you start to think you are not, remind yourself of at least 3 reasons you are.

People can want you, and when you start to think otherwise - think of 3 reasons it would be beneficial to others to have you in their life.

This is how I go about improving my self esteem. It takes a bit. Sometimes I have to speak it aloud to help myself remember, but after awhile - it sticks and it makes you stronger.