Rooms Full of Objects Disappear -- All at once!

I just had this happen to me.  I built a new basement room for party purposes, and I put about $65,000 into it: bars, buffet tables, dance floors, stereo, lights, everything...  Before the party started, I created some new outfits, but when I exited the clothing editor, the whole room vanished; all of the stuff, floors, walls, everything.  The back sides of the walls vanished as well.  any help with this would be appreciated.