Possibly could have an encounter with her digestive system, digestive hormones,changing your diet affect your anger issues or weather changes,she might even has any low blood pressure issues!
not every aggressive behavior should be get connected with curses or magic categories.
not every thing is magic related. there is a couple of thing other than magical related. she could have caught a cold, a virus even just have not been eating the right things her body needs. she could have caught a disease and she might even be pregnent and much more. Her being cursed is possible but i wouldnt think so soon with out looking in to it and that is a big mabye she being cursed.