Your worth as a human being is a birthright. No one can give it to you or take it away. You are a worthy individual. Don't listen to an inner critic. And treat yourself with compassion.
Compassion is the core of self-esteem.
It is a skill that you can acquire and improve. Understanding yourself only means that you have some idea of how you operate and why you operate that way. You typically know what you will do in a given situation. Acceptance means you acknowledge the facts while suspending all value judgment. Forgiving yourself means you let go of an incident of the past without dwelling on it or making yourself feel miserable all over again.