World didn't save all.

Hello, i have a problem here. Server suddenly lagged and stopped out of nowhere. When i got back, everything's saved except my coordinate (i spawned on the coordinate from my previous saved file before this one) and item inventory (all i have also items from the previous saved file before this one), but everything else is saved. Building and item inside chest saved well. Only my coordinate, i spawned in the previous save before this one, and my item also from tha previous saved file before this one. What's the problem? What i can do to fix what already happened? (My bad. I didn't back up yet). And what i should do to avoid this problem from happening again in the future? Thank you.

Ah, to be clear. On aternos (server), it worked well. There's no problem when i rejoined/restarted server. This problem only happened when i tried to play the world in single player (when i downloaded it from Aternos). I used the NBT editor you suggested on other thread to open the level.dat file, and yeah inside the file it does say that my player spawn coordinate and inventory are the same to the previous saved file before this one. Look like Aternos didn't update it to the current ones. I have tried to rejoin/restart the server again, all worked well there. My spawn state and inventory are the current ones. I have done /save all command several times. It saved. But still my player state and inventory isn't updated once i downloaded the world file.

Problem's solved. Thank you.