I think that at first in such a situation you have to keep calm and do not make quick decisions, especially to sell your bitcoins at low prices. Usually overall panic on the market is artificial creation intended to have huge profit from it.
Those who manage to remain calm in this moment of panic will recover their investments soon (and at a profit!). But those who sell in the panic of the moment, will see the asset returning to good levels and thinking: "why I did not hold? If I sold today, I would have made a profit!".