What is the consequence to living life with self realism behavior?

It is very typical to live life with self realism behavior and aware every time with our daily routine. When i sit and think about my past life i just found, there was a time which has been gone and never will come back, things has been happening and passing from our eyes, we are just going, going and keep continuing. I am just feeling sad about passing time, where am i going and where will i reach. We just follow daily routines as per humanity following. I want to know what should we our work, which could give us a full flicit and after following that way, there should not be any sadness and should be full of awareness.