The decision of when to cut your losses is one of the toughest questions in trading. Generally, some people will tell you never to lose more than ~2% of principle in any trade; however, it's not necessary easy to follow that in practice, especially when trading highly volatile markets.
win and loss is the part of game and trading is just like a game and good player is that who can learn from their loss because if you don't deal your loss with good impression then you are proving that you are not a good player and you will lose your confident so whenever you can face a loss then you need to find out your mistake and can find solution for that mistake so that in future you never you repeat your previous mistake and through this way you can become a success trader.