A lot of christians don't understand this, many people assume heaven and hell are these far off places, but these are just names for a state of being.

Heaven is a choice to be close to God. Hell is a choice to be away from God. So if you don't believe in God, why would you ever want to be close to God? Why would you go to Heaven? And if God is really God, then God is everywhere. In all places at once. My personal take is that some people spend their lives running from God, because they continue to seek the pleasures of sin. They only escape when they die. They create their own personal hell right here on earth.

And others spend their lives seeking God by following the Law written on their hearts. They spend their lives with God, and get to actually feel peace. When they die, they are finally complete and purified and get to join God.

Just keep doing what your doing, you'll find yourself believing in the impossible before you know it. You'll find that doing good just in case hell exists is not enough to motivate you to do good all the time. And then you might realize that you can't do it all alone after all.