Cramer is getting nervous about the big financials. "They stopped going up with the rest of the market and that's never a good sign ahead of earnings," he said.
Cramer worries that nasty headwinds are swirling– and they may be strong enough to derail gains in the entire sector.
"One of the headwinds is old and the other is new," Cramer said.
The old one is regulation and Cramer said this headwind is like the proverbial gift that keeps on giving – that is, it just doesn't quit.
"The Feds are changing the rules, again," Cramer said. "This week they suggested that banks need to raise more capital."
That is, regulators have proposed the nation's largest banks increase their ratio of equity to loans and other assets from 3 percent to 5 percent. If adopted, the rule would take effect in 2018 and would apply to U.S. banks considered so big that solvency issues could threaten the global financial system. Banks affected by the proposal include Goldman Sachs, Citigroup, Bank of America, JPMorgan Chase, Wells Fargo, Morgan Stanley, Bank of New York Mellon and State Street Bank.
That alone is enough to spook investors.