The stuff is getting deleted

The game itself is not saving the data, and it is really bothering me.

*What I expected to happen was that the game will have saved everything like 0.5.0
Describe what you thought should happen here

*What actually happened was that all of my stuff I built, was all gone, and only my inventory had stuufs in it.
Describe what happened here

Steps to Reproduce:
1. Make a new world.
2. Build something(a house)
3. Go out of the game, and its gone