Honest Existential questions about Christianity.

So I'm trying to stay with my faith, but there is just somethings that I have trouble grappling on when it comes to some of the beliefs Christianity holds.

For one, us as Christians believe that when we die, we go into eternity, with our unique individuality, however we don't mention where we were before we were born, it's like we just say that at the moment of conception, God created the soul and put it in the body. The reason why this doesn't make sense to me is that if we are going to eternity, doesn't it make sense that we came from eternity? Something I noticed about psychology is that nobody cares about where we came from, but now that we are alive, we forget about our "pre birth" (if it exists) and just assume we are going to eternity from a non eternal state because now that we are experiencing life, we don't want to leave it. I hate to take this atheistic - like standpoint but it does kind of feel like it was something man-made by human beings.

Secondly, something about our "unique individuality" isn't clicking when I think deeper about it. If we truly want to respect the concept of "individuality" then it would force me to think of what "I" really is. What would have happened if my mom decided to mate with another person? would "I" still be "I"? Then what about all the possible "individuals" that could have been born that wasn't born?

The atheistic concept of we go into "nothingness" when we die doesn't make sense either. Some propose that when we die, we go to the state we were before we were born, however if that were true, what's stopping this "consiousness" from coming right back to the Earth as new babies are being made every minute?

After thinking deeply about this, the concept that makes the most sense is that we all one and there is no such thing as "individuality" on the grand scheme of things. It does truly feel like when you die, you lose all sense of "self" and just return to the vast consious expanse, kind of like a drop returning to the ocean. This would account for all the births being made freely on Earth or who knows some other planet far off. In fact, I can't really say "you" come back to Earth, that's the barrier of language, but i'd say it's just "consiousness happening" when that "consiousness happens" then you can decide to put in egotistical attributes to it.

I don't know if you're still reading to this point, but I want to end this off by saying I do believe Jesus was a real person and he may have contradicted some of what i've said, in fact, evidence is he truly lived and if we are to take the eyewitness accounts seriously, sure it may have seem like he proposed the concept of individuality (if we're to interpret the gospels like that), which is what makes this so mind bendingingly confusing to me.

Thanks for reading.