Worlds are erased after one day of created

Hi! I don't know if this bug happens to anyone else or it's just me, but all the worlds I create are erase after one day, I mean it's like if I start the Minecraft from zero but all the setting modifications are saved.  This happens too with textures I import. I recently bought the game from play store and this stills happens and so it is a little bit unfair because I can't play properly. I hope someone can give me an answer, have a nice day!