Are we are doomed to be destroyed?

No matter what we do, if we avoid being hit by a meteor, a nuclear holocaust, catastrophic global warming - when the sun goes supernova that'll be it, all traces of humanity gone, all we have created, learnt - even our detritus - whoosh all a bit burnt & crispy in the blink of an eye. So what is the point? People often say "it'll not make any difference in a hundred years" so what about in 4.5 billion.