Mistakes are routine life in trading, so getting dissapointed due to these things is completely meaningless and might lead to losses more, if you keep on worrying about past disappointments
When you failed and losses most of money, the best things to do is review. Know why you failed and learn from it. Don't stop and try again.
Besides it, it is better not to sell anything when you feel you can lose the money you have. Take a break - go somewhere, for instance. Do not be in a hurry to get rid of the cryptocurrency you own.