The existence of negative news about bitcoin that can affect the decline in bitcoin prices, supply and demand can also affect the price of bitcoin. If bidding is more than demand, the price of bitcoin will drop and if demand is more than bidding, the price of bitcoin will rise.
Yeah it happens when a lot of people says bad about anything so it affect the market t value and the price of that specific object, so does happen to bitcoin, it is not good to let such thing effect our income, the other thing is panic selling, it makes price low, most of time sharks and manipulating whales use to sell at panic just to make the price down and then again they buy at cheap price so never sell at panic, it could be a way to trap your profit and this act of you will make price down.