Froggy has great friends.^^ But it looks like Hook-Bang never did anything nice to anyone which is unbelievable... She made the sheep plush for Sheep Nun after all for example. Maybe Froggy feels also in general less confident without Sheep? She helped her over being homesick after all....
I also think that Froggy and Sheep probably knew each other before the Convent, growing up on neighboring farms, they probably saw each other often.