I feel it too. The market keeps going up seemingly unaware that the world is a mess, the Country is in less than perfect shape, and people are not as happy as they should be to support a bull market that is at all time highs.
Just use your ability to analyze prices on a chart to be your guide and stay with the trend. Buy when prices seem to be points when buyers besides yourself seem to come in (support) and manage the risk of being wrong with whatever risk management strategy works for you.
Check out these charts:
P.S: ZYNGA mentioned in the review just got clobbered and is down 14%. Always pay attention to earnings. FB pops, ZYNGA drops. There is risk holding over earnings.