Autosaves seem to not have worked making me lose hours of progress?

I saved the game manually yesterday before I slept. Today, I made 4 hours of progress on my game, and it autosaved a lot of times. I shut down the PC and when I turned it back on and opened my game file it was yesterday's manual file that appeared???

Am I clicking the wrong file or something?

Yeah. The auto save file should be in the same folder as the original with the name "projectname.capx.autosave". Rename it to "projectname.capx" and open it in Construct.