File contents changed, message prompt confusing led to loss of data


I was working with a particular file. I saved the file before logging off. The next time I logged in and opened the workspace, the file appeared in the open file section with content I did not recognize. I was prompted that the file was changed on disc and asked if I wanted to reload it. This was a bit of a confusing message. I assumed if I did not reload it, what was on disk were my recent changes and would be kept if I said no. However, what happened is the file on disc reverted to what I was seeing in the opened version and all that changes I made to the file were lost. I’ve been working with this file for weeks and this is the first time this happened. I have no Idea what triggered it or why the version in the editor reverted to the content before I started editing it.