life

im going to live about 75 years? to me sounds like a long time but really its nothing and in that 75 years what am i supposed to do? what is the point of my life? what will i contribute to the world? if i didnt exist would anyones life be changed? what if i die young short of the average lifespan will i have acomplished what god wanted me to do? and with the time i have will i make it worth while? when i die will i be happy with the life i have. i dont want to die the kind of person who has no one to care for them. tied in their work not really happy. im scared about what kind of person i will be and who s life i changed if any.