Is it difficult for you to let go? Do you hold on to things for long? If you do then you are piling up a lot of burden on yourself and making yourself suffer. You cannot correct many things but what is most important for you is YOU itself rather than holding onto something which is past. You must think about your present.
If you want to live your present well you have let go your past else you will only live in your past. You must look forward and see how you can make things better. You have to let go of frustration, anger, failure and emotions. This will bring lot of inner peace to you. Everything in this world is not in your control so if you try to fix everything you are bound to get disappointments.
Handle your disappointments by letting go of emotions which does not matter much to your future. Focus on present to create a beautiful future.
Cheers,
Zustfine