Well bitcoin's price keeps changing due to several reasons. One of it basically due to supply and demand the wide fluctuations.And as we know the price is just rocketing up , increasing a percentage every day. The more the price is going up the more amount investors are putting into this crypto which is again resulting to price rise making it a cumulative process. As long as the prevailing bias of the market participants towards this currency is positive its price will grow indefinitely and after some bad news or any other unfortunate the prevailing bias would reverse its direction , dropping its price rapidly. Yes,so think rationally before investing in it.