What's to be done? If I fall down on my knees and wail, "Oh how could I have been so wrong?" will it change things? Not according the way your religion has been presented to me.
Now, if there's wriggle room, I'd say, "JC, if you're half the guy your PR says you are, I think you'll get me. You say, second only to loving God, loving one another is the most important rule (Mark 12:28-31). Now, that's just a rephrasing of you what you call, in Matthew 7:12, the summation of all the law and the writings of the prophets. Now, since this golden rule has been enshrined in religions and philosophies from long before your first human incarnation, and because it makes so much sense, I've lived my life by it. Furthermore, in the parable of the sheep and the goats (Matthew 25:31–46), you say that when a person does kindnesses for the least of your children, the prisoners, the sick, the impoverished, it's as if they are doing those kindnesses to you yourself. I've done a lot of that. So, in loving my fellow man, I've actually been loving you, which, is your first most important law. Are you really willing to cast me to eternal torment, just because I never professed a belief in you, despite the fact that I have acted according to your two most important rules, not for hope of reward, but merely because I felt it was the right thing to do? If that's the kind of deity you are, just cast me in the lake o' fire."
The question you need to ask yourself is, does the image of non-believers screaming and crying and wailing "Oh, how could we have been so very wrong?" provide you with smug self-satisfaction? If so, you may want to examine your own motives and question whether you are a true sheep of the shepherd or are you a goat, claiming you love your lord, but not acting accordingly?