There are many causes of low self esteem. It is a largely unrecognised condition that controls your life, reduces your enjoyment of life, causes you to not succeed in life, either in the work environment or in personal relationships. Especially, you might allow yourself to be badly treated by other people - or treat other people badly - and you might not be ambitious for yourself or your children. You might not realise just how low your self esteem is. Working to improve your self worth is something you can do for yourself.
For more information: https://www.mind.org.uk/media/715750/how-to-increase-your-self-esteem-2013.pdf