Supply and demand. The price is very fickle because people are. People panic sell and buy whenever there is bad or good news. Both these things impact the value of bitcoin drastically. I would look at bitcoin as somewhere in between gold and stocks and shares because whilst it is a currency at heart it's also a limited asset like gold and that's why Bitcoin is probably always going to be seen as speculative asset or at least for the near future so you're really going to have to get used to the price swings and if this is something you can't handle I don't think bitcoin is right for you. However, if it wasn't for the price swings and people speculating on it you wouldn't be able to make any money of profit on it.