It is always happening in any kind of cryptocurrency that when it dramatically increase its value it will surely fall back soon after hitting a certain amount, for the reason that short term investors are taking their profits and we have seen this a lot of times, Now Bitcoin drops from $17000+ to $13000+ but you don't need to worry about that instead it is a great opportunity to buy and hold more Bitcoin and take your profit after the correction. Correction is healthy in any kind of market (stock, cryptocurrency) because if the value of cryptocurrency or asset always goes up then people will not want to invest because it is too expensive.