Don't worry about being embarrassed! Those critters can find their way in to just about anywhere. Several years ago, when we were living in our old house (which had a large field accross the street) I didn't know we had a mouse problem. One day I was sitting in the floor pulling out boxes of cereal to organize a bottom cabinet with my dd (2 at the time) in my lap and my cat sitting right beside us. Well, one of the boxes fell over and a mouse ran out of it right in front of us! I was shocked and the cat never moved, so I guess he was a little taken off guard as well (or maybe just too well fed

). It was years before I could eat cereal again. I now use Tupperware type containers to store cereal in so I can see exactly what is inside.
We soon found out that mice had eaten through our HVAC duct work underneath our house and were coming up through the vents. We were losing a lot of heat/AC which I know cost us on our electric bills. In addition, it ended up costing us several thousand dollars to have all of the duct work replaced. (In our new house, I insisted on the hard ducts hoping we wouldn't have to go through that again!)
Hope you can figure out how to keep them out of your house!