Many dedicated thinkers over many hundreds of years have invested all of their mental energies into tackling this question.
The only answer that can be proven to be true without falling back into religion is simply that there is no meaning to life, that there is no purpose behind our lives. The best you can do is find a meaning to your own life by doing something that gives your life meaning and purpose.
The world and by extension the universe appears to be purposeless when considered from a materialistic point of view. If you look at the world through a spiritual or religious lens in order to find meaning you then are delving into that which cannot be proven as not everyone has a religious or mystical* sense and of those that do, results vary greatly and say more about the inner state of that particular person and the culture they were raised in or live in than what we can expect in the afterlife (should there be one) .
Have a look at this link.
*Please note that I will happily say all of this as a mystic myself, if you believe in God then you also need to consider that God may well be a purposeless being just like you and me and everything else that exists.