One of the ultimate curiosities of cosmology is the origin of the cosmos, and the first step in answering this question is to look at the big bang. Assuming our ideas of causality hold true in this instance, the question is begged; what came before the big bang? However, science does not have a solid answer to this question. The mathematical rules and laws of the universe do not function the same way when we approach the moment of the Big Bang, as well as the idea of before.
So what was the "Big Before"? From where, or what, did the Big Bang emerge? Well, we don't know...not for certain anyway. Still, there are some ideas out there. Now despite the fact that we cannot say for certain what happened before the Big Bang, we can still use the scientific method to form some idea about what append before the big bang. You may be familiar with the the inverse of the Big Bang: the Big Crunch, in which the universe comes crashing back into itself at the end of its life. A variation of this theory is that the Big Crunch leads to a following Big Bang, which is followed by expansion, then contraction; a cycle of unique universes. The name given to this is the Big Bounce.
So it is logical to assume with the Big Bounce theory that if our universe will lead to successive universes, that there was a universe before us, but how different was this prior universe from ours? How did it's laws of physics compare? If the Big Bounce theory were true, or the Multiverse theory for that matter, we would presumably find universes (if we could search for them) much different from our own.
So, if there was a universe prior to the Big Bang, was it like ours? That is to say, did it have the same laws of physics and the same way of doing things that our universe does? We might have an idea of this. This is a very difficult subject to study, as nothing is really preserved across the "bounce", so that makes observation impossible. Still, that hasn't stopped us searching anyway. Alejandro Corichi and Parampreet Singh, physicists at Universidad Nacional Autónoma de México and Perimeter Institute for Theoretical Physics in Ontario, respectively, have modified the "quantum constraint" of Loop Quantum Gravity (LQG) theory and claim that some universal properties are conserved across the "bounce". Without getting too technical, they say there is reason to believe the universe prior to ours would have had the same laws of physics, and be overall similar to ours.
They do stress, however that this does not mean the previous universe was exactly the same as ours, with another Earth and another you. It's more like the universes are twins of one another, in the sense of being for the most part identical, but still being unique. If our universe is headed for collapse, their models could predict what our future universe would be like.
A young physicist named Peter Lynds gained attention in 2003 for publication of his controversial article: "Time and Classical and Quantum Mechanics: Indeterminacy vs. Discontinuity." Lynds suggested that each time the universe "bounced", it repeated it's history exactly the same way. This means there were other "you's" reading this article, and there will be more of you in the future, who continue to read this article. Lynd's ideas were met with much criticism, and he has since fallen out of the public eye. He has not published many articles, and he only finished six months of university before dropping out (please don't follow suit, kids.) Though some hailed him as a genius, others viewed his work as mere philosophy, due to their lack of mathematical models.
So maybe Lynds is wrong, though his and ideas similar to his are still on the table. Perhaps you can salvage your individuality. Unfortunately, there are other ideas that still put your uniqueness under threat. The Multiverse Theory has gained traction in recent history, with developments in quantum physics. Simply, this means there are universes other than our own. The exact number of alternative universes is unknown, but it is postulated there are infinite universes and many different realities within each universe. Were that true, it would be impossible for there to not be another you - someone with your life, experiences, and habits, somewhere out there. You just have to search far enough to find them.