It's been a long time since I've logged in here ... like since 2009-ish. Amazed that I even remember my password.
But I thought to pop in, and see if there is anyone here who is familiar. Have a number of the Sims 3 games, so I'm starting to delve back into the game.
Did you download a new hack? Maybe something you recently downloaded is the culprit. Try removing the new additions, and see if one of them is the troublemaker. If you can see your stuff at that point, reinstall them again one by one to see which one it is. This is time consuming, but well worth the effort.