Autodesk Revit Architecture

[#1]

I am currently a student and started my semster project in Revit Architecture 2012 that is a vailable for use in the classroom lab. I opened up my file in Revit Architecture 2013 on my home computer and now it wont work on the 2012 version. I am afraid that i've lost all my work that i've put in and would like any help in recovering my lost work on 2012.

[#2]

there is no saving down in revit once its saved in 2013 its a 2013 file

[#3]

The importance of backups! Have you still got files in the project folder that are named with extra zeros i.e. 772.0016.rvt is a backup file of the project 772.rvt.  Possibly one of these could be copied then renamed to "yourprojectname.rvt" or similar and hopefully it is from a time before you saved over the file in revit 2013, and will still open.  Good luck.