ya, its true that you are here for a purpose.

there are chances.., chances that you are supportive role for a purpose, or the main role player for the purpose. how do you know about it.? this part is very complicated. for an instance, just rewind back some incidents in your life where you have been a cause or effect of some positive development, may be in any form- like a person might have developed because of you, or whole system might have developed just because of you.. or even may be you have stopped something terrible happening some where back.. all these add up to ur purpose on this land. the fact is, the purpose of your existence is clearly visible to u only at the right time of the incident. the vision is aware to u only after the happening of the purpose for which u r here.  this is not from any of the ethical books or stories. this is the fact many have experienced. so until u find ur purpose., the best thing u can do is wait, wait patiently until ur turn.. till that turn, do positive things. which benefits the environment in which u r living.