I experienced a bit of mental grogginess/fogginess and a slight headache along with a body temperature rise.
That’s a perfect description of die-off symptoms, which probably means that the kefir destroyed enough of the Candida to cause toxins to release in you body which in turn would have caused the symptoms you described. The temperature rise is the body’s natural defense against the toxins.
Are you taking precautions against the toxins? I’m talking about Molybdenum Amino Acid Chelate, Candidate from Native Remedies, milk thistle, and saunas as well as soaking in a hot tub of water for 20 minutes. All of these will help to lessen the die-off effects. If you take the Molybdenum at least and have a bit of soaking in the tub, then if you have symptoms you’ll at least know it’s from Candida and probably not die-off because you’ll be protecting yourself from this.
I’ll have to forgo the kefir route, because it will probably set me back.
You need to lose that frame of mind now. Kefir WILL NOT set you back once you get it right, and in fact maybe you’ve already gotten it right considering the symptoms you experienced. Try it again, because it’s doubtful that you’ll ever cure your infestation without kefir in your regimen as it’s the single most important supplement on the entire protocol. The diet is nothing without it because it’s impossible for the diet to cure the infestation alone, even with strong antifungals it won’t happen.