I love this show.
It comes on on Monday's in the states, and we didn't have a new episode yesterday.
This has to do with the way that American television works - the standard season runs from mid-September through Mid May - about 35 weeks. However, a typical televison show will only have from 23-26 new episodes during that season. December is usually a prime time for repeats for a number of reasons. First, November used to be a huge month for television due to a phenomenon called the "sweeps" period - television stations showed new shows, often special episodes with special guests in order to increase ratings, because the numbers from November were used to set advertising rates. Also, the with the holiday season in full force, networks don't want to run new programs during times of potential lower viewership.
look for new episodes in January.