As a human being, your only duty is that you grow to your full potential. If you grow to your full potential, your very way of being is absolutely useful. The best things will happen around you.
If you do not know how to make yourself happy, is there any possibility of you making the world a happy place to live in? If you do not know how to manage your body, mind and emotions, can you manage the world? So see how to nurture yourself to the highest possible level. Then you will do what you should do.