How have you gotten over disappointment?
Short answer: Sometimes you don’t.
Long answer: You learn how to integrate it and manage it by building emotional resilience and mental toughness.

Main Takeaways: 
Choose to learn what you can from the experience. 
Have radical honesty and acceptance about what went wrong. 
Know what’s reasonably within your control and understand the difference between disappointing yourself vs disappointing others. 
Move forward.