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.
He is right. It is never the end when the price hits down for weeks or a month. Not unless you sell it because of FUD. Which is not a good thing to do. So, the best track is to hold it for a while and wait for the market recovery. If it is really a good coin, it will recover.