Aside from the following,
1. Broaden your horizon
2. Have a program of life
3. Make a difference
What one can do to regain the life purpose?
I dont think anyone's purpose in life will lost. it's just that you do not know your real purpose in life and on earth. You are created by God for a purpose. Use your life to inspire other, be a blessing to other people and be a source of strength to those who are weak. Use your life to glorify God. Ask God what else you can do with your life.