I just started taking Kefir last night. I'm extremely hypersensitive and get detox symptoms whenever I start a new healing regime. Knowing this I only took a 1/2 teaspoon. I did get some mild detox symptoms but they were quite bearable. I will stay with 1/2 teaspoon or so until the detox symptoms subside. Then I will increase the dose extremely slowly. (When I started taking apple cider vinegar I worked my way up one drop at a time! I'm up to 68 drops now!)
You mentioned that you don't think drinking a very small amount of Kefir will do any good. If you are experiencing detox symptoms that is a sign that it is working! It's killing the bad bacteria, etc. and you are experiencing the side effects from this "healing" as the "bad guys" leave your system. This is a sign that even a very tiny amount is beneficial.
I would stop the Kefir for a few days to let the action subside in your system. Then start again with the smallest amount. Perhaps even 1/8 tsp. if you are very worried about getting sick. If you tolerate that dose with no problem try 1/4 tsp., etc. It will be worth it! Then work your way up slowly but surely.
I understand how frustrating it is to experience severe detox. You are not alone!