drawing changed after save

I spent two days creating a floor plan with the walls on a layer/tab which was grouped and locked. After placing all the furniture I saved my work and and went home with a job well done. This morning I opened it up and and the walls have all moved - not even together. I checked and the layer was still locked.

I am using LibreOffice 3.5.7.2
Build ID: 350m1(Build:2)
on Ubuntu 12.04

This is my first effort using Libreoffice. I put in quite a bit of effort learning the program from Youtube videos and websites and I am really disappointed that it ended up trashed like this. Could I have done something wrong?