Has anyone had a bad adverse reaction to fluoxetine?

Yes, certainly. You didn't specify whether or not the dose of fluoxetine in question would be a usual treating dose, or an overdose. In overdose, fluoxetine has been known to cause cardiac arrhythmias; but even in standardly prescribe doses, some pts may have severe nausea, headache, or excessive stimulation effects. In short, no medication is side-effect free; and there is a range of severity between people.