I've just converted to Atheism. What's next?

The difference between atheism and theism (besides the obvious) is that we are not dependent on deities to tell us what our goals or purposes in life are. So, after becoming atheist, you must find your own goal in life, one that is free from a deity. Any perfect deity would understand why you are atheist and would forgive you anyways. Perfection means lacking nothing, and that includes understanding. So, if the Judeo-Christian god does exist, and is perfect as they say, he would understand your reasonings, and would forgive for falling away.