I did not grow up in a Christian household nor one with any other theistic religion. Both parents being psychology majors, psychology was the closest thing to a religion in which I was raised. Psychology was the basis of the morality I constructed and science was the primary source of truth for me. When I asked my father about God, his reply was that He didn’t know. I became determined to find out what this God stuff was all about for myself. Years later he explained that the only possible God was one that had nothing to do with living our lives so He didn’t see how it mattered if God existed or not. But by then I had my own reasons to believe.
I am Christian now but my reasons for believing are not the usual ones. And I have heard stories of those losing their faith as you have, then finding new reasons to believe. This suggests that what is happening is that the reasons you had for believing don’t work anymore and perhaps you will find new reasons to believe. If not, I don’t think it is the end of the world. Christianity works for me but atheism seems like a rational option also. But if you choose atheism, don’t be too surprised if your children choose differently.