Where can an A4 diary hide?

I have now run out of ideas on where my large A4 diary might be.  I have been having a good look for the past three days and after thinking that it must have got put in my cupboard at school spent half an hour getting things out of said cupboard before the children arrived.  But to no avail.  I have now searched all the available places at home including cat cabin and still no diary - and I am desperate because I put in meetings that I think are supposed to be taking place next week.  My first week on the job as SENCO is not looking good!