Bitcoin prices have never been so low this year. Prices were down to 5,826.41$ (Jun 24 2018 16:04:00 UTC). Many advisers say that at the end of the year it will hit 30,000$. The market is seeing more than the fall from the price rise. Imagine when the speculation will end?
Obviously it will have a highest fall this year because the market prices last december 2017 already grow to its highest value and its down time is the next year, that's the reason it was falling today.