It's been a while since bitcoin had a major price correction. A 15-20% dip is normal, the people selling because of panic or FUD are those that bought at $3000.
This is a good time to buy, $2000 is a dream and elusive, this slump is temporary and the price will rise above the previous high in a week or two.
Even if there is a bigger slip up in the price of bitcoin,i would really hold till i get my moneys worth,one thing is certain when i am trading ,i will never sell my coins at a loss because i am pretty sure that it will come back to the old valuation at a later stage and only litecoin took a longer time for recovery from its old valuation,pretty much the rest of the coins have risen almost all of the time.