Problem with my video disappearing from my timeline and program screens

Hi, this is my first week using Adobe Premiere Pro and managed to make a whole video (40 mins). I was working on it, adding some audio, when suddenly it disappeared from my program and my timeline screens.  I have restarted the program, reset to saved layout, cleared my cache, looked everywhere but can no longer see or edit my video in timeline.  However, I just discovered that the whole video is exactly as I last saved it as an "IMG" in my Project screen, along with other of my downloads that went into creating this video.  When I click the IMG (which is my whole video) I can watch it in my source screen but still unable to see it in my timeline or my program screens. The audio, everything, is exactly as I left it. When I tried dragging the IMG file (the video) from Project into Timeline it looks like a short clip and won't play.  What's going on? How could I have been working on it fine one moment and then everything screwed up suddenly? Can I restore it so I can continue editing it? I was almost done.  Please help! Super frustrated with this program.