Indeed, it's normal because all coins do like Bitcoin and Ethereum and there should be always a correction everyone the price surges high.
Hold your coins as long you can and time will come when they're pumping then you can do whatever you want, either hold more or dump.
You're absolutely right, this kind of situation was already been happen way back a year ago. During the first quarter if 2017, most altcoins was so dump as well as the value of bitcoin. I would say we don't need to panic but to wait and trust the bitcoin that it will be back to it's stabilized value as time goes by. In some point I don't know when but if want to hold just hold it to have a good profit in the future.