Theres a little panic selling thats happened this week thats why bitcoin price go down. But its not enough to make bitcoin price to go down deep. A normal strategy to make profit in a short period of time.
I guess some of the whales wants to make some movement. It's either the current price for this week is already enough for them to make profit, because that is $1,200+ and we know that it's already good enough. And that's they did sold some but I don't think that is panic selling, because if that is panic selling we are seeing the price now back lower at $1,100.
The price pf Bitcoin have remained impressive since 2016 leaving most speculators in profits, so it is not unlikely to see a sizable number of sells every time new high is made and that is entirely a different ball game from panic sell off. Nevertheless, panic selling most probably out of fear, uncertainty and doubt (FUD) is indispensable in any speculative market.
Since the bitcoin is quiet an unpredictable currency the price has been very volatile making it hard for people to stay still when they see the price goes down and not do nothing about it, because if for us small users the price going down by 10$ is not that much for large investors that could be a loss of millions of dollars, and the only way they could limit their losses is by selling early, before things get really bad.