You are here for a reason
We have a purpose in life, a job to do, a mission to fulfill.
What is it? Ask God. He knows.
EPHESIANS 1:11 NIV 11 In him we were also chosen, having been predestined according to the plan of him who works out everything in conformity with the purpose of his will,
Of course, I can only answer that question in general terms.
2 TIMOTHY 1:9 NKJ 9 who has saved us and called us with a holy calling, not according to our works, but according to His own purpose and grace which was given to us in Christ Jesus before time began,
As a parent, raising up child is important. Helping a friend is important. You never know how your actions may affect the world --
even through helping just one person. Don't just wait around for some "big purpose" -- for with God all the details are important -- even the "small" ones.
If you don't know your purpose, just do whatever you can to help the people around you. Through that, and walking with God, you will accomplish your purpose.