Black Monday is a dark song about dreading the rise of Monday morning each week, in a context of not knowing what your future is going to hold or how you are going to hang on day to day, when other people are presumably getting up and going to their stable jobs. It describes feeling lost and disenchanted with life and not even his friend/lover can lift him from the darkness of Black Monday. The phrase Black Monday is used generally to refer to a Monday when bad things happen.