Welcome to the dark side! ;-) Just take a deep breath and realize that there are many people here who've taken the same journey as you and are living happy, productive, fulfilling, godless lives.
Use us as a support. Ask questions, learn, bitch, cry. Whatever. That's what we're here for.
I love the quote from ex-evangelist minister, Dan Barker's mother when she became an atheist. She said, "I don't have to hate any more!"
Also British Olympian, Jonathan Edwards, who was formerly an evangelical Christian and hosted Britain's "Songs of Praise" television programme, now says:
"“Once you start asking yourself questions like, ‘How do I really know there is a God?’ you are already on the path to unbelief. During my documentary on St Paul, some experts raised the possibility that his spectacular conversion on the road to Damascus might have been caused by an epileptic fit. It made me realise that I had taken things for granted that were taught to me as a child without subjecting them to any kind of analysis. When you think about it rationally, it does seem incredibly improbable that there is a God.”
"There have also been issues to address in terms of my relationships with family and friends, many of whom are Christians. But I feel internally happier than at any time of my life, more content within my own skin. Maybe it is because I am not viewing the world through a specific set of spectacles.” "
Come on in, the water's fine! If you're a former Christian, I recommend the site ex-christian.net (also the group by the same name here on A/N). It helped me a lot with dealing with some of my old issues, like catching myself throwing up prayers and fears of hell. If you're still a minor and living with religious parents, you may want to join the young atheists group here, and learn how others deal with that (coming out or not). I didn't wake up from religion till my 20s so there's not much my family can do other than fear for my immortal soul.
Other than getting involved here, I guess I'd say read. Some books on my reading list (that I haven't gotten to yet) include Carl Sagan's "Demon Haunted World" and Robert Ingersoll's eassy "Extraordinary Popular Delusions and the Madness of Crowds" (written about 19th century American tent revivals, I think). One book I have read and highly recommend is Christopher Hitchen's "God is Not Great: How Religion Poisons Everything". If money is tight or having that on the bookshelf would be a problem (or if you just don't like reading) it's available as an audio book on YouTube.