There is no one clear reason for the sell-off, but the daily chart has been warning of a move for the last 2-3 weeks as a descending wedge (triangle) pattern took shape. I had originally envisaged a rise due to the strong hold of the support. However, the moment the horizontal support zone was broken, the sell-off accelerated all the way down around $8,000 before a small pullback.
Again, re-instating my main focus.. I will be waiting to go long, once price moves in my favour. I don't trade against the current trend, I follow it. If it's not moving up, I'll wait.