Elizabeth is all about heading back to Longbourn; her mother is all about getting them to stay as long as possible.
She figures that the longer Jane is at Netherfield, the greater the chances are of a proposal from Mr. Bingley, so she actually refuses to send a carriage to bring her daughters home—which just means that Elizabeth and Jane have to bum a ride from the Bingleys.
After one more day of recovery, they're heading home. Miss Bingley is sad to see Jane go, but she practically pushes Lizzy out the door.
Knowing that he only has to control his passion for one more day, Darcy avoids Elizabeth like she has cooties.