A few months back, Katie Holmes was on an upswing — she had a new movie, a trend-setting haircut and was constantly seen with her look-alike daughter Suri. How quickly things change! In the April 7 issue, Star exclusively reports that Katie is finally cracking under the strain of life with Tom Cruise.

When Katie recently lunched at her favorite restaurant, L.A.'s Joan's on Third, it was obvious that something was terribly wrong. She seemed exhausted, her skin was pale, and she looked feeble and emaciated. "She gave us a weak smile and wave before leaving out the back door," says an eyewitness at the restaurant. Once outside, a confused and unsteady Katie braced herself against the doorframe before her bodyguard carefully guided her into a waiting SUV.

Dizzy spells like this have become a frighteningly common occurrence for Katie over the past few weeks. As one source explains to Star, Katie has been suffering from splitting headaches that make her see black spots and feel faint. Another problem? Her weight. Although she's already rail thin, she feels pressure to be even slimmer and is obsessive about dieting.

Katie may never admit it, but sources say her superstar husband may be contributing to the debilitating headaches. His high energy is often hard to keep up with — and that, paired with her intense need to live up to his expectations, is really taking its toll, both mentally and physically.

"Katie doesn't get enough sleep — and hasn't for months now," says one insider. "She's tired and drained much of the day because Tom is so wired, and they stay awake until after midnight. He has boundless energy, and she just can't compete."

To complicate matters even further, while Tom goes off for days at a time ("His rule is 'You can be with me, but don't ask about it,'" says a source), Katie is overseeing the interior design of their lavish $35 million Beverly Hills mansion. "To him, the home is a status symbol," says a source, "so it's on Katie's shoulders to pull off something beyond magnificent, something Tom can brag about. She's giving herself headaches thinking about it and making herself sick.

Source: Star Magazine