Was my random drug test random?

My schedule was changed the evening before my shift, and I had to get there earlier and to a different department than I was anticipating,and was late to work cause I had to change into proper attire after realizing the change. My manager was a drunk ass hole to me the last time I saw him and started giving me shit (not drunk during this interaction obviously ) but I was pissed at him still and pissed about the change of schedule and lack of notice, he started giving me shit the I gave it right back. But my time off request just got approved after this incident and I was asked to take a “random drug test” I don’t do drugs so I know I’m fine there but am I going get back from vacation and get fired for some stupid reason?