Team project disappeared

Hey! So a few classmates and I were using premier pro to edit a video. We were all in possesion of different videos, so we created a team project so that everyone was able to edit it and put their media in. However, as we were editing we noticed that we couldn't see what the other people were working on. When I closed the project, I was sure to share my work with the group, and I made sure everyone else did the same. However, when we reopened the project, we found that it was completely blank for all of us. All of the work was gone. I checked on earlier versions of the project and it's the same thing, all blank. In the most recent version all of our media is in the media section, but the sequence is completely gone. Any idea what happened, how to get it back, or how to avoid it in the future?