The Standard & Poor's 500 gained 0.78 percent last week to halt its two-week losing streak. While the streak may have ended, the selling pressure and volatility caused big changes in the sentiment indicators.

Seeing how we had only had four losing weeks in 2013 prior to the two weeks of losses in late May, it was enough to instill a little fear in investors.

The Investors Intelligence report from last Wednesday showed a sharp drop in the bullish percentage from 52.1 percent to 45.8 percent. This is one of the biggest one-week declines I can recall in the 13 years of tracking this indicator.

The bearish percentage only increased 1 percent, from 19.8 to 20.8, and this left the ratio at 2.20.

While a reading above 2.0 is still leaning toward the bullish side, last week's reading is the lowest reading we have seen since the week of March 6.

The Investors Intelligence report wasn't the only sentiment indicator that showed an increase in skepticism. The CBOE Put/Call Ratio saw an increase in bearish sentiment as well.

The 21-day moving average on the put/call ratio dipped below 0.60 on May 20, but the bearish put activity increased over the past few weeks and the ratio moved back above that level last Wednesday.

While the sentiment certainly has shifted off of its bullish extremes, they are still leaning toward the optimistic side.