Purpose or the fear of lacking a purpose is the root of many demons in the minds of a lot of people, especially teens and young adults. A purpose is important to everyone because it is how each of us justifies our own existence. If you do not know what your purpose is now, make something that means something only to you. It could be a drawing you drew, a photograph you captured, a song you wrote or anything that reminds you to keep searching and keep building. You will understand that specific thing and that is all that matters.
Every single person exists for a reason and sometimes it takes a lot to figure that out, it sounds cliche but it is extremely true. The key to drowning out your doubt is to justify yourself to yourself. Tell yourself you're good at something you love and keep working towards continuous improvement.The only thing stopping you from discovering this is yourself and the demons or opponents inside your mind.
For some, a lack of purpose causes depression and suicidal thoughts and that is something that needs to be acknowledged. The battle for a purpose is an action process, not a thinking process, so there is a need to get out into the world and get a little wanderlust, that will make it easier to find yourself and also find what exactly it is you believe in. Use the earth to your advantage, it holds an important message about yourself.
The beginning of finding your purpose may not noticed until you are far into the action, keep going, do not focus on having to find it, just live and it will come to you. The idea of purpose is not all that complex of an idea even though the journey is challenging for many, whether the road traveled, you will reach the justification of your existence.