I don't get how to revert changes I made. My project stopped working so I want to go back to yesterday's version. I found yesterday's commit in the history and tried both 'checkout' and 'reset master to this commit', but it seemed to leave the files I made today and it still shows unsaved changes. Is that the way it's supposed to work? How do I just make it ERASE everything I have now and reload the project from yesterday?