My advancements screen says "there doesn't seem to be anything here" in 1.13 pre6

I just made a new survival world to try to get all the advancements, but when I pressed my advancements hotkey the window just said "there doesn't seem to be anything here... 😞"

Turns out, there was no advancements or loot tables folder in the data folder of my worldsave and I don't know how to get them back. This only has happened in 1.13pre6.