You may have clicked the File area (above the load order) and it resorted your load order. You can try clicking the Mod Index area to see if that fixes it. You can also click the Auto Sort button on the right side. It is also a good idea to check for updates, so you click on the Help menu and then Check for update. That way you will have the latest load order list available. If you are worried about losing the order you have now (besides Fallout3.esm being loaded where it is), just click the Load Order menu, and select Copy to clipboard, and then paste into a note/wordpad