has a problem loading a world

I made a new survival world and this happens on all worlds too. I join in play some and leave, next day I come back join again and leave properly, and let it save I come back try to load in for a third time and says had trouble loading into world. I restart Minecraft and load in and it resets the whole world I'm back at spawn with nothing its the same for every single world. Make a world join, leave, join, leave, and try to join again and it doesn't work, restart Minecraft and it resets the whole world. how do I fix this Mojang because I really wanna play Minecraft again. as well as its in the same order for all world with leaving and rejoining.