Markets decline....and Crypto Currencies sold off even further....

Markets have been declining and its been hard to figure out what the underlying issues are.
From what I can gather there are some competing theories. I'm still unsure where I stand on the drivers of the sell off but here is what I know as being the reasons.

Tether - further scrutiny about this ICO and the fact that its backed by dollars makes it a antithesis to Bitcoin.
The regulatory review of the exchange called Bitfinex that Tether created it. Analysts have long suspected that investors on Bitfinex had been artificially inflating the price of Bitcoin. Bloomberg reported that the Justice Department is investigating Bitfinex and Tether Ltd. to determine whether people were using the Tether token to buy Bitcoin in a wash trading scheme. With the looming threat of an indictment, it could be that Bitcoin is falling closer to its actual value because it is no longer being artificially propped up. Tether has denied the allegations.
Bitcoin Cash - Hard Fork - which is a real issue because its drawing further investors away from Bitcoin.
Further regulation and legal review of various ICOs (Paragon, Airfox) where the regulators are suspecting that there are too many scams with the ICO communities.

These are just four drivers. I'm sure there are more. So what do you do? Buy? Sell? Hold?

I think my gut reaction is that you don't waste a good crisis. If you have all along bought into the idea of decentralization and the future of Fiat and Blockchain, then I think you use these moments to just buy some more. Heck, you're already underwater....doubling down now you're playing HERO ball.

What am I doing? Having seen my portfolio more than halve, I'm adding some more. Hard to believe that Bitcoin is now in the $3K, I think its not a bad idea.

PS sorry but my images are not able to upload....not sure why. But will try and resolve this....