Yes I did, but the money did not just vanish. The $10 is sitting right in the pocket of the person you bought the stock from. It did not go away. The money did not disappear.
You buy an ounce of silver for $20 and the price drops to $15, the $5 lost did not vanish either. It went to the guy you bought it from. Stock, comic books, commodities like gold, or anything else, it is the same way. Value may have been lost, but value is not real, it is an estimate. The actual money spent went into the pocket of the person who sold it,it did not go away.
Look back to the reference I made in selling a car. You advertise a car for $2,500 and sell it for $2,000. The $500 did not vanish, it never existed in the first place. You did not loose $500, it never existed in the first place.