Being sober, my short term memory improved. I also started to remember things from many years gone by. The longer i don't drink, the more I remember.
These memories don't make me happy, but they are real. Your post describes many of them well.
I think its the human condition, to feel pain when you are finally old enough to have lived a part of your life, and to think back on it, the things that were not perfect. To learn from the past, we must remember it, not run away from it...and applying what we have learned, means living in and appreciating the fleeting nature of the present...appreciating the coworkers you have now, this moment in time, b/c you have gained the wisdom to know these moments don't last forever.
It is painful. It is the human condition. Only the unwise would say you are alone in this experience.