You probably put it somewhere else and was thinking of something else when you did it! How many times have we all done that? I am sure it will turn up.
A few years ago, my dh and I was in MO and when we came home I couldn't find my favorite pajamas, I was just sick. I called the hotel and nogo. I couldn't beleive I did that, I tore my house apart looking for them for weeks. They were my favorite! Finally resigned myself to the fact that I lost them and left them at the hotel. A year later I was in my attic digging through a old trunk of clothes and there they were! How in the world did they get there? :) Point learned here though, use clear bags for this type of thing.