Actually the bread crumb is showing you exactly where you are.
In Windows 7, the "Library" concept was introduced, which is like a folder for your folders or a meta-folder if you will. You can add folders from all over your PC and across networks to a library so that you can easily access all the contents through one click.
Your Documents library contains the traditional My Documents and most likely a folder called Public Documents (though I have seen one build of Windows 7 without Public Documents). By default, the My Documents folder is set as the save location. Which basically means when creating in, saving to, or copying to the Documents library, the file will be saved in the My Documents folder.
You'll notice you can expand the Documents library in Windows Explorer by clicking on the arrow to its left. There it will list the actual folders in the library. The one you are concerned with, if I am not mistaken, is My Documents.
So when you click on Documents you are actually seeing the contents of all the folders in the Documents library, which for you is most likely My Documents and Public Documents. But Public Documents is probably empty.
If you really want to see the bread crumb for My Documents you need to access My Documents directly and not through the Documents library.
Now about Search Results. I am not quite how would a bread crumb could even work here. Search Results don't really exist anywhere (well they do but I don't see the point of accessing them via bread crumb). Search Results were created then and there when you performed a search, so you are kind of at the root of the trail.
Best Answer
The search bar horizontal size can be changed by grabbing the space between the search bar and the reload button left of it (see the screenshot below). Move the mouse into this area to find the correct spot (the cursor will change to a left-right arrow).