I herxed really hard on those meds, and while my dx is for a different thing, taking an allergy med (singulair) really helped with the herx symptoms. You could try something more moderate like benadryl to see if that helps? just a thought. I do believe you are herxing but would be scared as well. My vision was really fuzzy when I was herxing and that scared the heck out of me.
Also you could try taking lower dosage or not every day dosing to see if that can help make the herxing more manageable.