As I understand it, this is a normal part of crypto volatility. The value drops for some weird reason - someone tweeted something, somebody who had a lot of stake sold it off to manipulate the value. This is all going to happen when the adoption rate is less than 1%. As it rises, individuals will have way less power to control these markets and some, like bitcoin with its 21m cap, will be completely unaffected by any attempts to manipulate.
We just have to HODL, because that is what we do.