Calm down. Apple is no weaker than it was in September, and neither Google nor Samsung are any stronger. The market has turned against Apple because the street got irrationally exuberant, and a lot of investors followed them up - which was a perfect setup for the traders to knock it down as soon as daily volume lagged.
You're not the worst investor unless you sell and bake in your losses without a plan. Do you have a good advisor? Speak to him/her, get their help in constructing a balanced portfolio, and whether or not selling AAPL here makes sense for you. AAPL is my largest single stock holding, and yet, as it's been slaughtered, my portfolio value has been stable or very slightly up. I've just bought some more healthcare - I own IHE, and it's done very well, up more than 17% since I bought it less than a year ago, and today bought some XLV, to dilute out my AAPL.