Crypto is a world of miracles and biggest disappointments so the question arises how to stay calm in difficult situations if you are a holder(Person who does not do short term trading) not a trader.
A person who buys crypto or any other stock after considering all the risk associated with the coin can become impatient in these situations. Some coins gain value very quickly and start to decline more rapidly.
The key to remain calm is to reconsider the criteria that you made when you were investing. Your criteria can be wrong or right but it will be always right for you until you consider it wrong this will give your mind relaxation but if you have found that your criteria of choosing the asset was wrong than you should immediately test all the investments according to new criteria and than change the investment.
When you start loosing money than the only thing comes into mind is to save the profits or stop loss and mind stop thinking about the logical reasons to hold the coins. The best way is to keep searching about the technologies when you are in profit so that you can easily understand the logic of holding any coin or not.