Certain parts of world "Respawned"

I was playing survival in 19w14b and noticed that the first 1.14 pre-release had come out . So I quickly saved and quit, updated my game and loaded straight back into the world. The problem? It deleted all of my chests, my on-wall maps, enchanting table, doors, half the entire house, and some other items. In it's place was grass and flowers. I really should have backed up my world but I thought "It was just bug fixes. How much harm can that do??"

First pics: what happened Last pics: sort of how it looked