In 2.24 "Winston's Birthday," Jess's friend Peg gets her a job at the school where she works, yet Peg is nowhere in sight when Jess now complains she can't make any teacher friends at the new school. It's certainly possible Peg stopped working there, yet this is a detail the show should offer rather than leaving it up to viewer guesses.
In the teachers' lounge when Nick is inviting the clique to his bar, the camera cuts from Jess with her lips pursed and hair frazzled to Jess looking completely normal.