I'm going to let you in on a secret. There are always going to be doubters in any secular bull market. As bull markets progress the Beanies of the world will come out of the woodwork and tell you with great confidence that this is a bubble and the end is near. Some can even make a pretty convincing argument. I suggest when you start to buy into this nonsense you proceed to the
beat your head against the wall technique. Remember no one can see into the future. You don't make money in bull markets by getting shaken off the bull after a couple of points. You make money by holding on. Just because the market is overbought is no reason to exit. Bull markets get overbought and they stay overbought for long periods of time. They make new highs. That's what bull markets do, they go UP.