Since last week, I've lost %10 of my total holdings (btc-wise) and its counting.
I will never sell because selling means losing. I still didn't take the loss, coins will go back up sooner or later anyway!
If you are holding your coins its mean that yet you have nothing lost, i think that if the price once fell down then there is no use to sell your coin in such a law price, in fact it is the nature of the crypto market that after every downfall the price always recover its position and therefore we should try to stay calm and hold our coins for some good time.