My doubts have never been because I feel I don’t have enough information, or that Christianity has some sort of internal inconsistencies. I think I’m cynical and pessimistic by nature, and have chronic depersonalization disorder (well, self-diagnosed). When I doubt, my thoughts are along the lines of, “Yes, all that makes sense, but what if we’re missing something…. what if the truth about the world isn’t beautiful and hopeful and good, but behind everything is, instead, some terrible truth that will consign us to eternal torment because we have missed something?”
I look at people of other faiths who are assured of their being right, and think, “couldn’t that be me, too?” The role depersonalization plays in this is that it makes me feel not real, makes me question my own existence, and can be accompanied with paralyzing fear/anxiety that is just utter darkness. I don’t feel these doubts acutely all the time, or even that often, but I wish that I could shake the feeling that Christianity isn’t real in the same way that the chair I’m sitting on is real.