My senior who used to introduce me to Bitcoin and Cryptocurrency once said that the decline in the price of Bitcoin and other coins could happen at any time and we couldn't predict beforehand.
So if one day I go through something like this, please stay calm and don't panic, such conditions are normal and will definitely happen often.
One message for me, if you invest, choose a good coin, so that when there is a decline, it still has the potential to go up again.