I'm going to get all sciencey again for a few minutes. I just watched an episode of the Universe series on Discovery channel. It never ceases to amaze me how so many geniuses can often miss the coolest implications of their own conclusions.
Okay, here's the Cliff Notes version: Galaxies come together in clusters, over time the clusters cluster into super-clusters. Eventually, they merge into one big super-galaxy, but the various super-galaxies continue to move away from each other so that, in umpteen bajillion years or so, if you were in our supergalaxy and had no record of the past, as far as you could tell our supergalaxy would be the entire universe. You would not be able to detect the others. They would be too far away.
While they commented on the possibility that future sentients might not be aware of the real size and scope of the universe, they seemed to miss the distinct possibility, or extreme probability, that neither do we. Especially given the recent discovery that our universe seems to be getting pulled toward something ultra massive beyond the cosmic horizon.
Why would one assume that we are at the beginning of such a cycle? It seems more logical that what we know as the universe was once part of something much larger and that when our neighborhood becomes this "supergalaxy" it too will separate into clusters which will go their own ways.
No need for panic though. For one thing the time spans involved are unimaginably long and for another, there really is no limit to how small a universe can get. Everything is relative.