if I were you, then I would stay HOLD and not sell during a decline, because you will lose your money, therefore I always recommend to investing using money that will not be used in the near future, so if the price of cryptocurrency that you invest is down, then you will not worry and can HOLD until the price increases again, so you can get profit again without having to panic sell (lose your money).
It's just a method that should be followed by everyone who wants to invest, because by using money that is not used for other things, it will always be free from the burden of thoughts when a price decline in the market occurs, only some people who dare will not care about this.