Overlapping media deleted original work

I started using Rush about half a year ago to work on a video for college applications (I want to major in film). Today I went back to make a change to a section in the middle of my video, importing a new piece of media to replace it. Usually when importing new media, if there's anything behind it it will be moved to make room, but go right back to its place when you move the new media. This time, however, that did not happen and all of my work (about 2 minutes worth) was completely deleted from the project. I didn't realize until after working for a few minutes, so I can no longer hit the undo button to get the work back. I have a copy saved in another location that I can use as a reference to rebuild it, but is there any way to just get back what I did? Please help.