I believe that you lose only when you sell a cryptocurrency and you stay for example with dollars and -10%, but if you see that the price of your coins has decreased by 10% and you do not sell, it does not count as a loss, because prices will return to the previous level and your coins will cost more than before, when you bought them. Everyone who lost money selling his coins during the fall, I advise now to buy and wait for growth, because at the moment there is a return of the bullish trend.