You need to be very cautious with terminology and the conception of Big Bang Cosmology. The Big Bang model basically states “the observable universe was once very hot and very dense, and the began to expand”.
Does this mean the entire universe came from a single point? Well, maybe not. First of all when we look at the statement above, we have to look at the term “observable”. We can extrapolate that the parts of the universe we cannot observe, because of the horizon problem, behave like the parts we can see, but unfortunately it will take billions of years worth of observation to determine if that is the case.
In general, the “single point” is more a product of the break down of our current physical equations break down when you down below the Planck distance and Planck time. In other words, the “point” is a singularity, where the math starts becoming gibberish. So that’s always a sign of a big hole in our knowledge.
There are theories, admittedly long from being confirmed or falsified, that would suggest our universe is a “bubble” in a much larger metaverse, so even if our universe has a finite beginning, that’s not to say that existence, if you define that as everything that is (all the universes), could not ultimately be infinite as well.
Even if you don’t buy into brane theory (and I certainly have my issues with it), it’s also possible that the Universe may be cyclical, periods of expansion, terminating in a “big crunch” where everything gets super hot and super dense again. A lot depends on what the cosmological constant ultimately is, but it should also be noted that we appear to be living through another inflationary epoch, with the expansion speeding up, which invokes the dark energy (which was responsible for the inflationary phase early in the Universe’s history), so maybe the end of the Universe is really just going to be the hypothesized “heat death” where in the end every structure in the universe dissolves into a fog of subatomic particles at nearly maximum entropy.