First, sorry to hear of your not pleasant experiences with water kefir.
Second, I had very similar reactions to water kefir and had to finally stop.
I started kefiring and a few days into it I came down with a horrible UTI. Thinking "die-off" i continued. I got a bladder infection. kept on, several other uti's. My friend came over and drank some kefir, that night she came down with a bladder infection. I now know that the yeast content in the kefir was too strong and have since stopped the kefir drinking. I also want to say I haven't had a uti before or after the water kefir epidemic.
Kefir is not for me.