Sunni Islam. I can't say I fit into a specific school of thought any more specific.
Until I was well into my teens, I didn't care much about faith. I didn't pray the majority of the time, I'd fast on Ramadan but that's about the most religious thing about me. It isn't even about whether I believed or not. I knew there was a God, but I didn't really care much. I suppose I could've been called an "apantheist", but that isn't to say I was completely and utterly apathetic to religion as a whole. The only real reason I did fast at the time was because I felt like I had to, it was a gut feeling I suppose.
I've become more religious over time. This is probably TMI but I'm schizo (I don't know how else to say it, being that the word has lost all its meaning in the face of wacky cyberpunk Tumblr art and surreal fashwave edits, I was diagnosed and all). I believed God spoke to me, and I believed that He told me that no matter what I do, I am beyond His mercy, and I'll end up in Hell no matter what. What didn't help was my sleeping schedule and near complete isolation. The only people I spoke to in my real life were my parents. When you're in that position, having dropped off the face of the Earth, it forced me to contemplate it all. I started taking meds, I started praying, I started truly believing in God. That's really it, frankly.