EVERYONE is nervous the first time. Took me weeks to commit to it. Way too many dire warnings. At the moment of truth I stared at my ES for a half an hour before I could make myself drink it. Other than shuddering at the taste, nothing dire happened. By the next day (no stones my first flush, just a lot of chaffe and debris) my attitude changed to much ado about nothing.
I stopped counting past 3 dozen flushes. I believe that whatever process creates stones doesn't stop just because you flush out what's already there. Flushing treats a symptom, not a cause. Never-the-less you are clearing out the liver and gall bladder to keeping working more efficiently.
You don't change the oil and filter in your car once, or even a dozen times, and expect it to stay forever clean.
You are dealing with diet, lifestyle and genetics.
You should be eating and eliminating regularly before flushing.