Maybe tryt o put her on B1, which is a calming supplement, until she calms down and leaarns to respect you.
Actually that's true. Friend of mine had a mule, which suddenly started to explode for no reason (actually sending my friend to ER couple times). One day he just dropped dead and the autopsy (spell?) showed the poor creature did have a tumor in head.I heard that a horse that is that bad could have a brain tumor.