World “Destroyed”

When I started to play the new update to Minecraft on PS4 it asked to convert one of my old worlds to the new version of Minecraft and when it finally converted I found that the house I built and railroad track I made just were gone and was placed with a different part of a world all the stuff I had were gone and all the animals I had were gone too only half of my friends houses which was filled with sheep farms just gone.  Is there anyway to revert back to the old version and get that world back without it destroying all our hard work