So many tokens these days are based off the Ethereum platform, so I daresay that unless there's another alternative that those projects can 'easily' transfer to, then there's always going to be a use case for Ethereum.
Yes it has gone up and down constantly, but guess what, everything else has, Bitcoin included. Since post-Christmas, the market has been so volatile, so for the most case, the ups and downs of coins are just natural.

If you're holding ETH and are worried, I'd suggest potentially closing Blockfolio, take a break from the crazy crypto world, and focus your attention elsewhere; it can be healthy!

Good luck!

-Knightly