I had a similar experience. I was raised in a Conservative/Fundamentalist Christian environment. Sometime shortly after undergrad, I realised I didn't believe those things anymore, and how many were logically indefensible. I now identify as a Progressive Christian, sometimes leaning toward Deism.
I believe in God, as a fact, from philosophical arguments. Primarily First Cause and the Ontological Argument (maths minor here). Logically demonstrating Jesus is God is a bit harder, but, I think he was about as good as any man who lived, and the absence of evidence isn't evidence of absence, so, eh. Theologically, I'm at a point where I'm not sure it matters. One of my favorite quotes is a paraphrase of Marcus Aurelius,
I have a lot of friends who outright rejected Theism when confronted with the indefensible. Which I understand, but don't agree with. I think that rejection is often a continuation of the black-and-white philosophy of Fundamentalism and Conservatism. When faced with incontrovertible facts against black, it's easy to flip to white, rather than recognising it's not "black" which is wrong, so much as the dualistic worldview itself.
Again, I lean toward Deism. I'd like to believe in an afterlife, but I don't think it would be the horror many people think if there isn't. Time doesn't cease to exist after it happens, if that makes any sense. As Mark Twain said, "I do not fear death. I had been dead for billions and billions of years before I was born, and had not suffered the slightest inconvenience from it."
Yes. Though I wouldn't say my belief is fading away. I'd rather say I deconstructed my faith and rejected the indefensible, and am now rebuilding it.
I'd add, I think a great many people, especially Fundamentalists, mistake God for themselves. That is, "God" is whatever they want and whatever supports them. That may mean rationalising their selfishness, or it may mean condemning vices they dislike in themselves. But regardless, it's self-worship, and bad. It's something I actively think about and try to avoid in myself. And also, just because many people worship themselves and call it God, doesn't mean a real, impartial, omnipotent God doesn't exist.
I'd also add, that I think "good" and "evil" are immature misconceptions. People aren't "evil", they're broken. The conservative theology of eternal damnation is childish. The philosophy of punishment because people "deserve it" is childish. People need helped, and fixed, not "punished" because they're "bad". Children think "bad actions are punished"; adults realise "bad actions are given negative reinforcement to teach good behavior". The purpose of all pain is learning, not some warped concept of justice. Suffering is bad. It takes a sick or childish mind to think otherwise.
You might be interested in Fowler's theory of Stages of Faith.
Marcus Aurelius' Meditations is also a fantastic read, but especially for anyone caught between fanaticism and atheism. It doesn't have answers, so much as advice for living well, and honest, rational thought.