Evolution = No afterlife?

I've been atheist for over 5 years. Staying positive is much harder when in the end I believe that there is nothing after death. I mean I try to just live and not worry about it but I find myself thinking about it all the time. Since evolution has been proven, (fossils, human genome 96% chimp, etc.) then we are just talking animals when it all comes down to it. We die the same way every other creature on Earth does. Everything you are is in your brain and body. Once your brain decomposes that's it your gone. Only your atoms still exist. It's pretty sad. It seems like an afterlife is impossible in reality. But at least the atoms are recycled create more life. If death is the end then human existence doesn't even matter? It's only a meaningless spec in this super big universe? Not being negative just realistic.