The should have, could have and would have is getting you down, it is the spirit of regret. It has a place, but once overgrown it becomes a seed of depression, doubt and defeat.
Be mindful, be careful and stand guard around your heart, refuse to allow disappointment to become desolation. Be deliberate in not allowing situations to become systems of thinking and believing.
What is done is done and what is missed is missed, look forward to your next opportunity, with this new found wisdom. Savor this feeling and learn the lesson, fully.
With the right angle and velocity a rock can be thrown to skip the distance of a lake. Change your angle on things and find a new velocity allowing you to skip over troubles.
Brothers, I do not consider that I have made it my own. But one thing I do: forgetting what lies behind and straining forward to what lies ahead, I press on toward the goal for the prize of the upward call of God in Christ Jesus