The same thing happened to me, and all was fine until I tried to download the resource editor onto my computer (you know, the button that says "my computer").
So, I had originally created a couple of little packs. Nothing strange. They disappeared, but I just made some new ones. Now, these new ones are the ones I want. When I clicked the button to download the resource thing onto my computer, it reverted my packs back to before I had any I really wanted. Is there any way I can access these files again? I'm using Google Chrome, if it helps.