I really don't believe this to be a "drop" in bitcoin price. It's simply a correction back to where it really should be, when you see it rise from $5k to $20k in a matter of weeks...all amid a very crappy transaction throughput and fees with no real fix in sight, .you KNOW it was just quickie investors and of course then a drop is coming, that simply is unsustainable growth in any sector anyway.
I would say, based on where it started going nuts (about the same time as futures trading was announced), price will stabilize around $6-8k.
All my math pans out so long as price doesn't go below $4 or 5k....so, I'm still quite happy, i've never actually bought bitcoin from cash, it's always been mined or paid to me, but I may buy some soon!! The only time I used an exchange was to cash out free BCH. If your math was based on $16 or $20k....i'm sorry for you, but...that's just silly based on where it was just a few weeks ago.
As the old time expert investors say, humans are wired to buy when it's going nuts and bail out when it's dropping, exactly the opposite of what any good investor does. Besides, if your holding bitcoin as a means of investment alone...that may be a mistake in it of itself and at the very least with the past history of extreme volatility, you need to be fully prepared to lose your investment and not get upset about it.... Just my 2 satoshis