For me , low self esteem was a by product of anger. anger towards others and anger at myself for not living up to others standards. I also set the bar way too high for myself. My goals and feelings of self worth were simply unattainable and very low because of my mental makeup.
As time went on I lost everything. I felt lower than low because of the things I had done and the way I felt about myself. It brought me to the edge of the cliff.
It takes time and considerable effort. Much therapy , and finally being told that I WAS worth something and had much to offer regardless of what others or MYSELF thought.
There are methods out there to help you change how you feel about yourself regardless of negative self perception. Don't try and do this alone. Hang in there long enough to let the miracle happen.
Best to you