The teen mom-to-be is in such denial about her condition, another source says, that she's "trying to go about her life as she always did. She still hangs out until late at night and eats junk food."
Jamie Lynn isn't used to her new shape yet and feels enormous, even though her bump is barely showing.
"A male friend joked at a party that she looked sexier with her new curves, and Jamie Lynn snapped back, 'Shut up!' She then turned to another friend and said, 'I hate my body!'" another source tells Star.
Despite temperatures in Kentwood reaching into the 70s, Jamie Lynn has been out wearing heavy sweatshirts.
"Jamie Lynn is having severe bodyimage issues," adds the insider. "For the past few years, she's been this cute little TV star. Now she sees herself ballooning — and she can't handle it."