Top Charts show the comparison between 2017 and 2019 right after Bitcoin hit 10,000 mark.
Bottom chart is showing what happened in 2017 after the Dead Cross happened.

Death Cross: System's Fair Price index cross over(Green x Blue)

As of yesterday, Green System Median Fair price was 9989 and Blue System Median Fair Price was 11757.

In 2017, it happened in a week after touched Green line.
But I don't think it would happen that quickly in 2019 as the slope of blue line is steady downward rather than stiff downward compare to 2017.

Fundamentally, Bitcoin should keep the bullish momentum until next May however if above death cross is occurs, protecting your investment is highly advised.

But for now, 8700 is the key turn around point.
If ever breaks down 9000, 8700 must hold up and you can see right away with very strong bounce(Immediate recovery over 9000).
Otherwise BTC will be in very tough spot to regain the momentum.