Look for what you want in life, and try to strive to be the best that you can be. Your purpose isn't always going to just appear out of nowhere, and sometimes, you have to look outside of yourself in order to try to find your role, to decide the fate you want for yourself.
A life without purpose is an empty thing, and from my own experience, not having a purpose is nearly as empty as death itself. A life without purpose is more often than not a life without drive, a life without joy.
Your purpose has to be self ordained, and it has to be something that you yourself desire. How can you strive for something that you yourself not believe in? How can you find joy in a life without the purpose to drive you on? Happiness is more fleeting when you're living day to day.
Look outside yourself. Talk with others. Travel. Explore. Do whatever it takes to find the purpose that you so desire. Don't let other dissuade you from your dreams. Live the life that you wish to live (within reason), and find your own purpose in life. Find the one thing that you can strive for, something that can keep you moving forward.