This is what people call an "<em>existential crisis</em>".
<u>It is a moment in which an individual questions if their life has meaning, purpose, or value.</u>
<em>Now on a religious note</em>, most people believe that that the ultimate purpose of living is to re-connect with God and go back to the spiritual world where you came from.
We may believe that we will only die and sink in a dark hole of nothingness, but no one knows that. We have no knowledge of what happens in the after life. Though after a long time living in this world, you will begin to understand that you don't belong here. As you become older in this life you realize that without exception everything turns into misery, sorrow and frustration. This would be a depressing realization IF there were no positive alternative.
<em>Let's talk scientifically</em>. You were born because of the same purpose you were born for. To carry forward your species so that they don't become extinct. As you live your life you may find other purpose of life like helping others, doing something great, discovering something never discovered before, etc.
The purpose of your birth is as said. You need to find the purpose of living.