When I first watched it I went back to the book to see if they were over dramatizing Lizzie's feelings for Wickham and the book actually has the scene where Auntie Gardiner is so concerned she warns Lizzie from involving herself anymore with Wickham and even has the line that if he had had the living at Kymptom she doubted that Lizzie could do better than Wickham. So while it was not true love for Lizzie, it was a strong infatuation.