Is it normal for a female dog to become aggressive after being spayed?

I have just had my 6 month old female husky spayed and she has suddenly gone from being sweet and quite submissive to a bit of a hot-head. It's been almost 2 weeks since her operation and she isn't fully healed (although she is acting like it by running around all the time!), so I understand she may be feeling vulnerable. She never directs this anger toward me or my boyfriend, however has begun directing it at her brother (he has also been fixed so it's not down to him trying to have sex with her or anything). They had a fight today over absolutely nothing and I tried as hard as I could to separate them but she just kept launching at him every time I got her away. She eventually got mad with me trying to intervene and as she was trying to get at him, she bit my leg and it is now a bit bruised and swollen (before anyone says anything, I realise this was my own fault but it was getting out of hand. I had no choice!). Is it normal for them to behave like this when they have had this kind of operation? This really scared me and I had a bit of a panic attack afterwards because it has never took me so long to get them apart before. They usually stop as soon as I tell them to but this time they ignored me and just carried on. She has done this about 4 times since her operation, and every single time I have seen no clear reason for it (i.e. fighting for possession of food, toys etc). She just starts the fight and even when he is willing to back off, she won't stop and doesn't care if we are in the way.