It seems to me you fell asleep in December, woke up in the 2018 and started doing the market analysis before reading the news. There is this thing called bitcoin futures market which just launched and with that, some investors can invest in bitcoin without pushing up the price. Also, the fact that most US traders (which makes up a large minority of bitcoin traders) didn't have easy access to shorting bitcoin and only thought about how high bitcoin could go suddenly heard short getting thrown around in December means FOMO buying season is over. I only hesitate to go full Bruce Lee on this post because some of the sites that let you do leverage trading don't accept US customers.