Most people will tend to sell their currency out of fear during a market downturn. If you are holding altcoins, you should stop the loss in time to reduce the risk. It is better to lose a small amount than to lose all your funds. Be patient when holding Bitcoin, trusting that the market will rebound and the gains will continue to be reaped.
You are kind of thinking that it is the end of the life of altcoin. Not all have fear over this; others will take this as an opportunity to purchase more and gain more assets. You won't be losing your funds if you are smart, like if you know the cause of the downtrend and predict that it will be up again, since it will also be your loss if you sell it and after a few months the price goes high.