A friend of the 31-year-old told In Touch magazine, "She doesn't want to leave her baby. Sometimes she just starts crying. It's hard for her.
"She's so emotional," added the friend, "She doesn't want to go to the gym."
With the pressure of a $4 million Weight Watchers contract looming, it's not as if Jess has a choice in the matter.
She has been hired by the weight loss company to drop 23kg in just five months.
But could the responsibility be too much for the blonde bombshell?
"[Jess] is consumed with the new baby. She and [husband] Eric are often up with Maxi [Maxwell] all night," a source told RadarOnline.com.
"She gets so upset. She wants her body back so badly, but it's beyond hard," said the source.