Mama bear?

Have any of you had mama bear come out and became super protective about your bump? I was driving through an intersection and had to swerve and slam on my brakes because another driver flew through his red light. I felt this surge of anger, got on his tail, and laid on the horn for a good while. I know he got the picture. I was so mad that he almost hurt my baby!! I've never been angry behind the wheel and I can count on one hand how many times I've used my horn. Is this due to the extra hormones???