Actually, you are right in that "one day" it's like the light bulb came on in my brain... this is all horseshit!! It felt like a smack to the back of the head and literally I felt embarrassed at first when I noticed how stupid I'd been.
As a child, I was very skeptical as none of it really made sense, but I was surrounded by those who said that they believed. I thought I was missing something or that god was overlooking communicating to me. I knew something was wrong with me. I watched science shows (NOVA was a favorite, still is) and nothing I heard in the theories of physics even remotely related to a god. It wasn't until many years later that I realized how people are brainwashed into believing what they would otherwise consider bullshit if heard inside a court room, or worse, on the bench in front of the post office.
My final attempt to believe occurred in college with bible study sessions. I didn't do anything for me. I gave up on religion and considered myself a lost cause. Oddly during that time I didn't seek out information about atheism. If I happened upon it, I read it. That was rare.
Like the letter writer above - I would jump to apologetics to explain any challenge - ignoring the logical leaps, the contradictions and the verbal gymnastics required to salvage the "sacred texts" from the concept of error.
You have an advantage that I never did. You believed. I cannot say what it is like to transition from belief to non-belief. I am amazed that anyone believes this stuff at all, so I continue to be lost in understanding how people get sucked into it. The closest I can claim is transferring from agnosticism to atheisim, mainly due to a misunderstanding of both terms.
Learning more about how religion affects everything, or to directly quote Hitchens, "Religion poisons everything", you will begin to see how you may become a born-again atheist. Hitch was definitely a born-again atheist.