It always happen when bitcoin's price drops and people start to speculate that it will drop more or some negative news.But keep in mind that usually there is no base for their speculations and it just spread FUD,which might make new people who had recently bought to panic sell seeing their portfolio drop therefore causing more drop in bitcoin's price.Every drop you would see these FUDs to spread, just do your own research and see what's really happening.These drops are great opportunities to buy more and just hold.