When small things tend to let you down in life, it is useful to think of the really wonderful things.
In my case, I remember how wonderful the achievements of Newton and Einstein have been, what a sense of bewilderments the fruits of the strivings of these giants have given to humanity. I also ponder the beautiful moments in the music of Mozart, Beethoven, and Wagner. I remember the poignant depiction of the human condition in Yasujizo Ozu films.
Remembering all these wonderful things gives me a sense of value and goal in life. I would not dare call this perception absolute or Platonic without the modern "small prints". Whatever the nature, the remembrance of these wonderful things serves as the "polar" star in the night sky of my mentality, the immovable and guiding principle in life.
That is not to say that small things in life would go away. These troubles would still torture me from time to time. It is only that I can become immune to some extent, thanks to the smile and joy the remembrance of beautiful things brings to my soul.