I try not to let disappointment get the better of me.  Happiness and sorrow are bound to each other.  To know happiness is to know sorrow.  Within this richness is the joy in living.  When things are not going as planned, when you have loss, or disappointment, even failure, it's all part of the bigger picture.

Sometimes, I don't even see the bigger picture until later, when I reflect.  But in the day I keep moving, and I learn from the failures, which makes me greater now.