My guess is hitting 10 000 was a milestone for a lot of people and it went as high as 11.5k+ earlier today then a whale sold off or something and here is the problem with a bunch of people who own a % selling.. they create a snowball effect and others panic and get scared and start selling. How low will it go? No one knows as for long term hodlers you have nothing to worry about : ). So just hold
Disclaimer: this is not financial advise trade at your own risk
Bitcoin falling after reaching a tremendous all time high is very common. It is an inevitable to see some holders to sell some of their BTCs after reaching a certain target. This is just the way it is so just bear with it.
In every community, there will always be those who have weak hands and are playing always on the safe side. So if a so called whale began to dump, some weaklings follow and watch the domino effect.
For the record, it is good for Bitcoin to go down once in a while. This way, some will continue to buy when Bitcoin had its corrections.