I have tried taking S. Boulardii and drinking homemade kombucha (which contains S Boulardii). I react to both the same way - headache, sinus issues. Makes me feel like I have a bad cold. I know it's the S. Boulardii - taking a Nystatin makes me feel 100% better (I assume it's killing the S. Boulardii yeast) and that I have a yeast sensitivity from the candida. Weird thing is, I'm fine with water kefir. Probably because it has different yeast strains. I'm wondering if I continue to drink the kombucha, will my body eventually become used to it? It has so many benefits. Ughh :( any thoughts? thank you.