All Minecraft items are missing

I have been playing on an SSP world in Minecraft 1.7.10 for a few weeks now. I had played offline for a while because I was in a place with no internet. When I returned to having internet access, I had not realized that "Use Latest Verson" had been selected. For a little while I played on the most recent snapshot and then decided I wanted to return to the one with which I started the world. Anyway, when I loaded the world back in 1.7.10, all my items in my inventory, chests, furnaces, etc were missing. Can this be reversed?