A little correction, 2017 was bullish and 2018 was the bearish season. And it's indeed no sign of bearish run yet this year. Institutions, big names, and companies are still in a trend of entering the crypto market. So, that's enough reason for the bullrun to continue, but that's not guaranteed as well. Once the whales starts dumping Btc, the price will follow suit.
$15,000 might be the sharpest drop If Btc dumps.
Many times for bitcoin go bearish but when it dump for thousands of bucks the whales execute their buy orders to support bitcoins and maybe this kind of scenario are the one we can experience this year and those heavy drop the same on year 2018 will not be seen since big supports from big investors are still hyping up the scene. And lets not focus about dumping possibilities since for sure this will not happen, the $100k discussion still floating and this is the new target to be reached by bitcoin.