As for tolerating it, it’s hard to say. At first, it gave me headaches and when I ate the grains I felt like I did after an 80bn probiotic capsule. Now it doesn’t really bother me at all. I’ve eaten 3/4 cup of grains in a day with a litre of kefir. Just start small and judge your reactions.
Your reaction sounds more like die-off to me. I have drank water kefir multiple times and I’m pretty sure that my symptoms are being worsened and not helped. As I’ve said before my experience with antifungals and diet are totally different–although there is some discomfort at first, I can feel my symptoms usually improve somewhat, whereas with water kefir, I can feel my symptoms progressively worsen and erase all the effort that I put in improving my condition through diet and antifungals. Maybe, it’s the sugar content, who knows? Again, this is just an individual testament, so each person may be different. And along with the severity of the condition, I’m also sure many people have different types of candida which require different forms of treatment.