Nothing happens! You die, and you're dead. Better make the most out of life, since it's really all you have.
I don't believe in an afterlife, or any sort of other worldly stuff, or a God (or gods). The evidence for all of that stuff is
always extremely flimsy, contradictory, not supported by science, prone to personal bias, prone to groupthink, and so on. If one day science exclaims, "Hey! There's something else after this life!", then I'll consider rethinking my views. I don't believe having 'faith' is enough to warrant a religious/spiritual belief - I need real evidence. I need something concrete to base my beliefs on.
But for now, I'll stick to what I see. To me, it's all I get.