I have a question for you Melissa. Please take a moment to carefully think of the implications before you answer. You said that you "used to be a Christian." So are you therefore saying that you knew the Lord. Is that correct?—because that’s the biblical definition of a Christian—to know the Lord? The answer creates a dilemma for someone who believes that she is an atheist.
If you answer "Yes," then you are admitting, as a professing atheist, that God does exist. So you are forced to default to "I thought I did. But I didn't." So you didn't know the Lord. You were never a Christian. You had a false conversion. You are not alone. Millions have had false conversions and they sit in churches faking it. The Bible calls them goats among the sheep (goats in Israel can’t be easily distinguished from sheep). You, however, like many other false converts didn't stay among Christians and fake it for too long. You left the church, and became inoculated against the Christianity that you believe didn’t deliver its promises.
Almost all in this category are the tragic result of a false gospel and they, like you, have been immunized against the truth. If you would like to know why and how you fell into deception, please take the time to listen to "Hell's Best Kept Secret" and then "True and False Conversion," on www.livingwaters.com These are free audios.