Mid of January become the day of correction after the bulls run and seem like bitcoin will recover by the end of January or in February such as happened in 2017 where bitcoin increases slowly over time. The cycle always repeated, maybe someone or a group of whales always do the same thing in the mid of January, to cash-out at the moment to give an opportunity for new adopters to enter the market at a lower price. Honestly, it's a good thing as most altcoins declined as well, buy more coins in the dip and sell at the peak.