I agree it'll be a bumpy ride, in crypto it always is!
Apparently about half of the ETH held by ICO's has been sold so far, so the worst could be over. I can't imagine them selling 100% of it all, there's bound to be a bunch of them who will hodl on to ETH so there can't be that many sellers left. But ETH isn't going anywhere, and patience is a virtue. I think PoS rewards are going to be a huge game changer economically for ETH - it has a huge drawing power to people looking for passive income and dividends