As crazy as it sounds, I think Learn2Live hit the nail on the head and you should thank your lucky stars she showed her true colors when she did - if she hadn't gone so ballistically crazy, you might have ended up married to this woman!
Deep breath - this too shall pass. It'll just suck in the meantime.
I wish my STBXAH had flipped out like that. Might have been a wake-up call for me...