Those sound like possible detox symptoms to me. I put a bit more than I should of boric acid in 2 cups of water once and got a headache soon after drinking it. Did you put the 1/8 tsp in 1 cup or 1 liter of water? Ted says the amount of borax/boron is for 1 liter :)
I didn't realize it's good for candida! I'll have to make an effort to supp with it.