If the Altcoin you hold can still be staked, that's even better because it will benefit from the interest.
Right now I'm also losing 80% of the Dollar Value I hold in Altcoins and I'm holding it until the market recovers it's better than I have to sell and lose 80% of the Dollar Value, but it's all up to you if you have something more important than holding it, it's better to sell it.