Looking at the bigger pricture since price has been dropping from ATH we have had 3 wave so far hit ceiling of the downward trendline. Following this trend would suggest that price will go all the way to 500, worse case as you say.
If you take a look at raw price action, we've already achieved a validation point of a down trend on the 17th. The market can change direction at the support levels listed ($800 & $690)
Note however that the bottom trend of the channel is still awaiting a validation point, which resides on the $500 level... A major support level as well which was established from November and December of 2017.
aformby
⋅
@EJSM, Thanks for the chart. :) Looking at the last wave it looks like we could be forming a monster H & S, which if played out would target us at 500 ish level