You should probably just get tested instead of speculating. That said, I would just say 'everything in moderation." That's what
I've learned these last two years of being primal / semi-primal. Anything in excess leads to problems.
You'll go to the restroom more because there's probiotic bacteria in yogurt At least, I think there is in Fage.
You can perhaps look into making kefir instead of buying yogurt -- it's a lot healthier (more probiotic bacteria) and fairly easy to make -- just need to find the grains.