The thing is that, the brain fog seems to have started 4 months after Antibiotic use and only after starting a new multi-strain probiotic. Moreover, my GI problems have improved during the period. I don't seem to have any other symptoms other than a slight fatigue. So, I am not completely sure whether this is candida, are there good ways to check? On the other hand this seems way too long for it to be a die-off/herx.