Well, do you know what is the most useless emotion one can ever have?
Ok so let me tell you what is the world's most useless emotion one can ever feel. And it is “self-pity”
The reason behind this is that this emotion is never felt but is always chosen by us when we fail to do something. What can be more worst when you pity yourself for something you did out of your caliber, mind and obviously talent. What we get by choosing this emotion is "nothing". Yes, we get nothing by being pity on oneself by doubting oneself.
Instead of being so pity and regretting, the best thing you can do was to learn from what you did and just move on. Thinking over and over again about the mistake you did, all you end up doing is doubting your self worth. This doubt will trap you in battle of depression and will end up making you irritated.
It is a request to all of you that learn from what happened and try to overcome the mistake. Just learn from it and don't think over and over again that it make you helpless.
After all the only thing that matters in the end is ones happiness and success.