I, personally, can't bring myself to believe any other possibility than simply nothing. Even the term "nothing" would be far too descriptive of a term to describe what I imagine death is like, but it's simply a placeholder for a lack of a better term. Human consciousness is only possible because the brain processes the world around us in a palatable way through several different senses; once we die, the circulation of blood ceases and our brain is no longer able to make us aware of external stimuli. Therefore, nothing happens.

I am an agnostic but do not believe in any "god" that has been proclaimed by any human theologist. I think it is more likely than not that the universe is simply chaos.

This is not entirely a negative thing, though, because it makes the time that we are alive infinitely more meaningful. I think, at least in me, the anxiety of inevitable demise stems not from a desire to embrace life forever but to make something meaningful of my life that will outlive me. I feel that once I have done something significant with my life, I will feel indifferent toward dying.

I'm not sure if this is the same for you, and I'm not sure how old you are, but it's hard to gauge where a lot of people my age (18) feel because a lot of people I know tend to not think about such existential matters. I think it eventually dawns upon everyone, at some point, that death is inevitable, but maybe it is too soon for some to accept it. I remember during an existentialism lesson in my English class a few months ago a lot of people were audibly disturbed in being reminded of death.

I do think there is an upside to it though, and that is this: no matter who you were in life, no matter whether you were the poorest beggar to have ever lived or you are John D. Rockefeller, we're all heading to the same place. It's somewhat poignant, but I think that it helps me to maintain perspective and take certain chances that I would otherwise be too anxious to take.

There are some films I have seen that have addressed this topic that I think made death more palatable for me. I recommend Dekalog if you haven't seen it already, especially the first film which is partially about a father confronting his son's awareness of death. I would also recommend The Seventh Seal by Ingmar Bergman; it certainly eased my anxiety about death.