All of the cryptocurrency market is tied one way or another to the Bitcoin price so when Bitcoin sneezes all the others catch a cold. Ethereum has great usage case as it is the main platform for launching other coins it won't end just because the price has dropped.
I also adhere to the idea that if ETH fell in price, then this is not the end of the market. I think, after a while the market will begin to restore its previous positions. Now all the coins are in decline, so you do not have to worry, just wait a bit.