help - white shapes highlighted as black

The white shapes in my document suddenly started appearing black - when I select the shapes, they still have a white fill, but are appearing black for some reason and I don't know how to fix the appearance. I must have accidentally hit some keyboard shortcut, but I have no idea which one. Anyone have any ideas?

And while I'm at it, is there any way to turn particular keyboard shortcuts off? It's really frustrating that this keeps happening.