Never let losses define you.
Learn to control emotions - Massive losses often lead investors to become emotional. This is normal. But how you handle these emotions is crucial. Emotional investors tend to act rashly. Don't do that. Don't be like a gambler in a casino - when you lose money, don't invest more to recover the losses. If necessary, take a break. Learn from mistakes - seek to understand where the problem lies. What is your trading style? What is your temperament? That.