If you keep saying sorry on small things, then this shows your low self-esteem. Say sorry only where you have actually made mistake.
Ever happened when someone gave you a compliment and you started shying away? This is low self-esteem.
You have a underconfident walk, you don't make eye contact. These are all actions by person with low self-esteem. Be yourself!
People with low self-esteem don't take care of themselves and see it waste of time. Start caring yourself.
If you are afraid of taking credit and compliments for your work and achievements, then you are person with low self-esteem.
You struggle to show and happiness to people then this shows your low self-esteem. Start being happy and show your love.
You try to avoid new experiences and adventures, in fear of exposing your joy and expressions. You have low self-esteem!