Changed Shift Times at My Workplace

This morning, when I finished my work shift at six and walked out of the building, it ended a two-year long stint working the late-night/early morning "graveyard shift".  Since the post office needs to process the mail passing through it in a prompt and efficient way in order to assure timely delivery, many of its workers in the mail processing section have these shifts.  It's what I started out doing in 1987 when I began my employment there and I worked these difficult hours for fifteen of my first sixteen years.  However, I never did get used to it and had much difficulty getting enough sleep.  Also, I believe it made me more susceptible to illness.  From 2003 to 2013, I was able to switch to an afternoon/evening shift and my sleeping patterns normalized, with my general health improving.  But due to my organization's sweeping consolidation decisions in the past few years,  my position with this preferred schedule was abolished...and I chose the best available post for me back on the late night shift.  Only this time, I was determined to stabilize my sleep by going straight to bed soon after I got home from work in the morning.  Still, on my days off I would revert back to sleeping like most of the world during those late night hours.  Although I handled this better than in the early years, I still felt that I was getting sick way too often.  So when the opportunity recently presented itself for me to switch back to an afternoon/evening shift, I jumped at it and got the position.  After a couple of days off, I will begin it this coming Monday afternoon...