Furnishings Gone From Lot After Moving

I need some help. So I just created a new house and everything to move my family into, but I wanted to keep the things they had at their old lot intact. I moved them into the house then tried to move another family into the old lot. When I tried to move them, it said I couldn't move into the old lot with furnishings. I then went to the lot to see and all the items had been moved. I've had a lot of sims live in that house and it's full of things I've collected and gravestones with ghosts I wanted to keep around. Now the items are gone, is there any way to get them back?