If you haven't sold, then you haven't loss anything. Stop comparing the highest price to what the price is now. You didn't sell at the top so it was never "your" money. Until the money is in your hands, it was never yours. Just comparing the highs to the lows will make you go crazy.
Well, you can and 10 years to keep and wait until vostanovitsya after a fall of 80% (if at all vostanovitsya). and you might need money tomorrow. I often sold in a minus and beat off on other coins. and they just stayed in the minuses