high p/e is justified for momo stock such as FB. your main focus should be whether the revenue/sales will grow or not. if the mm's don't see possible growth, your stock isn't worth much. look at AAPL, for an example. it has tons of cash and low p/e and yet it's tanking. why? because it's growth is limited.
don't love or hate your stock. just trade it.
i think FB will be a penny stock eventually, but i think it's gonna go up before it crashes. it might take several years.