It was just a matter of time before the value of bitcoin went down. Reasons are probably large ammount of bitcoinminers and peope who had alot of bitcoins sudenly selling them
It rapidly outgrew its value quite drastically so it rapidly fell back down. The figurative bubble popped. Bitcoin is incredibly volatile and that peak and enormous fall starting near $20,000 was a prime example of that. It's stabilized a little more, but I don't see it going anywhere for another year or so.
