player data not saving but world is

i have been playing on multiple single player survival worlds and after a while of playing i come across an issue and it makes it so i cant really play the game. So my player data isnt saving, so i play for a couple hours get work done in the world, then is leave and re- log go back into the world everything i got done in that time is still done but my inventory is back to the way is was before i started playing hours before and my cords and xp are back to where it was when i logged in earlier that day. ive tried re downloading the entire game  and deleting all the files loosing my worlds and it still hasnt fixed it, and the worlds i am having this issue with i have deleted the player nbt data in the level.dat folders but still hasnt worked really disappointing would really like to be able to play on my worlds again