How can i build my self esteem and confidence

Every person may have a sense of self worth which may or may not be accurate. As you noted you have felt this low self esteem since childhood. This self esteem or self worth is where beliefs and opinions were formed about yourself. High self esteem does not mean pride or inflated ego, but an honest opinion of self. However low self esteem does hint at close mindedness, self hate, self pity, and other such negative views. 

It takes work and determination but it is truly possible to change your concept of yourself and to build your self esteem. This is often where counseling can be helpful. 

A counselor/therapist can help you:

Believe in yourself-learn to love yourself and appreciate who you are. You have been living up to this low image of yourself, you want to reframe the negative views of yourself and appreciate yourself. 

Gather courage-take control of your life. Find things that you have the ability to change and work on those. 

Be optimistic-challenge negative self talk and challenge belief about self. Learn to listen to the negative self talk you have internally, and begin to challenge those thoughts with more helpful ones. 

Treat yourself well-Learn to enjoy yourself, find things you like to do.

Participate in life-build relationships, when you learn to love yourself you can begin to build and appreciate relationships with others. 

Be self-contained-learn to become self reliant and do not depend on others who do not appreciate you. When you are self-reliant your pride comes from things you do. 

Establish a purpose-assess your life values, and set goals that align with those values. 

Self-esteem is very important to be successful in life and protect yourself from being used. It creates a feel good factor which makes us like ourselves and others like us as well. Irrespective of how we fare in life, high self esteem always keeps us going and working towards something meaningful. Our self esteem must not depend on our success or failure or what other people think about us. It really depends on how we feel about ourselves and the messages we give ourself.