What to do in a situation like these:
1)Take a Deep breath (I know its obvious but do it)
2)Turn off News/feed regarding ethereum (it won't help you checking prices 10 times every second)
3)Do not absolutely do not panic sell (Most important Rule, there are whales waiting to buy your ethereum at cheap)
4)Remember why you Bought/hold/mine ethereum in the first place.
5)Wait till sanity returns to the market and go for a relaxing walk.
Todays Price crash etc will be forgotten in next month and solid tech like ethereum will survive and continue to grow.
Just look at that beautiful long term chart to remind yourself how far we have come...
Coinbase is Insured but not for your Ethereum only for the $/Eur/GBP that you have in cash in Coinbase/GDAX I believe in Coinbase and they will be able to fix the issue with Ethereum back-up those $13 ethereum transactions.
Incase you have forgotten or doubt Coinbase look at:
http://fortune.com/2015/01/20/coinbase-raises-75-million-in-largest-ever-vc-round-for-bitcoin-company/