First of all, make sure that it's not part of a herx already on going - just to be sure, since you are on the full Buhner protocol.
Have you tried increasing your magnesium intake? Also, what type of magnesium are you taking? Different types are better for different things. Here is a good listing of the different types and what they are best for:
www.globalhealingcenter.com/natural-health/types-of-magnesium/If this isn't helpful, this post will at least bump your thread back up to the top for advice on the Rifampin.