Whales and investors panic are the main cause. Whales have withdrawn most of their money from the market after they have earned horrible profits from last year. They haven't returned yet this year, so the price hasn't yet reached $20000.
We can't be sure if they haven't returned yet however institutional money is said to be the one that shall come next.
But once the bull came in, expect that no one can stop it and it can run until the end of the year. We have to realistic and on this very volatile market its a yes and no. These days, predicting is now harder than before but bullish people are encouraging that it will.