moved sims out, lost everything is there any chance I can have my decoration back after moving a family out of the house? Can I place them back or do something? Or do I have to redecorate all over again? :(
Yep. 'Fraid so. If you have NL or up you can put furniture and such things in sims inventories. By the sounds of things, you haven't, so you'll have to redecorate everything again.
Yeah, if you move the family out using the tool in the SimBin, it asks you if you're sure because the family will lose all their possessions. But if you have a house that you like to use a lot, you can place the lot, go into the house using Build/Buy mode (i.e. without putting a family there) and decorate it how you like it. Then, if you have one of the earlier EPs (I can't remember which one), you can move the lot to the LotBin and re-use it over and over.