You are special because of who you are - not because of what you do!
You need to have enough self-esteem to know that your time and effort is valuable. Don’t let others ignore that and don’t ignore it yourself. If others take advantage of you, it happens because you let them!
Low self-esteem lets people worry about what others think of them. Don't try to be perfect in your action and reaction. You are perfect as you are.
