How do you explain nothingness when you die?

Atheists claim that when you die that is the end. There is nothing else after. An eternity of nothing. I just can't see how you can experience nothing. In my mind, there has to be something. If you really think about it, how can that be? When you sleep, even when you don't remember, you are always dreaming. And you always wake up after. Nothing lasts forever, so atheism cannot be correct. What I'm looking for is an explaination for afterlife, just to give me an idea of what it might be. Thanks!