1. You should not be afraid and sell your bitcoins.
2. You should buy more bitcoins when their prices hit the bottom.
3. You have to persist and store your bitcoin for long.
There can be two kinds of strategy can be followed while the prices were falling the one is holding the coins until the market to recover or just sell at the current price and buy again at the bottom level and we can choose our strategy based on our investment time just like keep holding if you are long term investor or just buy and sell if you eant to make profits in short term.