How do I stop dwelling on the afterlife?

I can't stop thinking about it. Day after day, I contemplate what happens when we die. Or what doesn't happen. I don't believe in heaven or hell, but I just can't fathom not existing. How can that be? I know it's forever unknown but I just can't stop thinking about it. I keep wondering what I should do in this life, if there is an afterlife, so that I can be happy in the afterlife if it exists. It's horrible---I can't seem to stop wondering if anything happens when we die. Please no christian answers about hell or heaven---I don't believe in that, as I said before. The thing that I can believe in the most is reincarnation, but it feels empty. I can't stop thinking that maybe I'm just trying to believe it to get rid of my fear, but I'm so confused. Help!