Its not everyday or every situation that you will get to understand everything. Especially why or how they end up happening.
You may feel bad, angry, disappointed or even defeated. That feeling of being a fail may weigh you down. And make you doubt your previous efforts. Its okay, it happens.
Many thoughts will cross your mind. You will keep guessing and self doubting yourself. But this will only make things worst. And its not either to avoid all these that easy.
If pity party works for you. Please do but don't allow it eat you up. Be sad, scream, blow some steam. Do whatever you need to. Until that feeling goes away.
By doing so, its when you get to go past it. Its not easy as you may think. But it gets better with time. A little help and boast to your self will, you will be okay.