There are two possibilities for cryptocurrencies these days, particularly Cardano, for you to think.
The cryptocurrencies will fade and become worthless.
Soon or later, cryptocurrencies will rise again and grow.
If you chose to think of (1), you should sell all your coins now before it is too late to lose all. But think about this: in 2017, many serious team the first time introduced to the world their innovated technology and solution in blockchain. They have not even tasted the second year of development. Now you think their project will die ?? Is is not a joke ? So I think you are just a weak hand. You fear the loss. Ok, liberate yourself from this devil market. Cryptocurrency market seems not for you. The very normal thing of this market is extremely high volatility. Do you know why ? Ok, learn about it. It is not simple to explain for a newbie about the chaos orchid of a quite new invention of the human being.
But if you chose 2, you should be a holder because soon or later, you still get profit. But if a holder sell now to hope to buy the dip, that is just a gamble. No one knows what the next is. If you cut loss ? You actually really lose and then to win back. In contrast, just hold the coins and surely you will get profit later.
Of course, a holder like me is not a God not to feel pain when my investment to Cardano is now going down to only 2-3% of its original value. But it does not bother me too much. Think of it. You are investing to a very big project. The time for such a big project to fruit is years, not even months. The team is still there, everything planned is still there, the work is still there, and that is where we go with them and believe in the future profit.
P/S: I will not sell a half of my Cardano before it gets 5 USD.