In your answer to the letter Why would losing faith be such a bad thing?, you alluded to the college and grad school days you spent in rejection of Christian faith. I'm not trying to be nosy, but could you share some of your experiences from that time? The reason I ask is that I've spent the last few years in a steady spiritual decline. I've kept up the language and ideas of the faith, yet walked away from them completely in my actual life.
I hope you don't think that I'm nosy or just looking for something juicy. But what I really want is some real, actual evidence of what really turning away from God is really like, and what it takes to get back on the track, and what that's like too.
It's a good thing you're not looking for something juicy, because it wasn't like that. But for what it's worth, you're welcome to read the short version of my personal testimony, "Escape from Nihilism." If you'd rather read a longer, more philosophical version, look up the book Why I Am a Christian: Leading Thinkers Explain Why They Believe, edited by Norman L. Geisler and Paul K. Hoffman, and read my chapter "Why I Am Not an Atheist."
Your problem isn't unusual, although different people get into spiritual declines for different reasons. My own path out of faith, which lasted for a dozen years or so, began in a drift, not a flight. The most important piece of advice that I can give is to remember that there is no such thing as a solitary Christian; we are made for communion with our brothers and sisters in the faith. A lot of the reasons for drift are reflected in the Office Hours article "Cloud of Unbelief." I also give practical advice about how not to drift in How to Stay Christian in College.