I'm not too worried about Bitcoin, if it drops even below today's Price it is still optimistic, for me, I just hold it longer and wait for the bounce back.
What should be worried about is those who hold altcoins in big portions, this may be a dark time for altcoins, the price will fall deeply and make holders have a dilemma between holding or selling, and selling at a loss is better now before the decline is even deeper.
Past events should be a lesson, holding Bitcoin is still a better thing than holding altcoins
The altcoins are already at very low prices and most of them are on their strong support. Yes, they can dump more but not much. Also when you see that bitcoin dominance is at 65, how high can it go before falling ? Maybe it can move to 70 but then the dump in BTC. D is imminent and that would be bullish for the altcoins. It is only a matter of time. I know most of the people are holding altcoins for a long time, but those who can keep holding them during the current phase too, may be rewarded well in the near future.