The star reportedly whined to her family that she was exhausted jetting around the globe to promote the vampire movie.
A source told heat magazine: "Her family is worried. She's told them it's killing her."
The actress was forced to make a series of promotional visits in just a few days to make up for the absence of her co-star Robert Pattinson, who is currently busy filming Water For Elephants.
The source added that she has stopped eating and sleeping properly because of the stress of having to talk about herself in interviews.
"Kristen has been looking pale and drawn in the last couple of weeks."
"Her stylist told her to get a lighter hair colour to try to hide how ill she was looking. At one point, she was looking so gaunt that her eyes were almost popping out of her head."
