Hi, I am having similar issues with my male dog who was desexed last friday. He is normally submisive but the last coulpe of days has become very dominant. While out walking he has taken to barking and lunging at every dog that passes. He has never done that before. I have taken to making him sit until the dog has passed and then continued walking. I am hoping it will all settled down in the next 6 to 8 weeks.
Hope your girl settles down too.