now the price has returned to $ 19k and is likely to start rising until the end of December, it looks like it went down to $ 16k just to accommodate the bounce price! looks like it will touch $ 20k 
The volatility of the market involves buying and selling at the time the investors wants to make profit or the time that they want to buy for future profit, because investors are constantly buying and the market is moving every second, so expect the price to always move and up pump and get correction as long as no bad news coming and the whole community of investors are motivated to buy, we are good to go.