the sims 4, disappearing houses

could someone help me, i'm playing the sims 4 on pc & i tend to get a glitch where my houses disappear, it's happened a few times & i tend to keep having to start a new game over, this is getting boring now, as it's happened once again, only this time i've got quite far in the game, i dont wanna start over and lose all that i've done, how can i get my houses back, i've tried going back to the main menu without saving, i've even tried turning off the game completely logging off, but it still the same each time i go back on, there are either no houses on the map or when i do click on a house that is there, it doesnt appear on the street where the sims live, there is just an empty lot, please help!