It wasn't the lemonade causing this, because it happened a few times not taking any lemons.
Maybe lemon could be used as a purgative on purpuse. Usually it's something like salt if you want to induce vomiting.
Mine was like nothing I had ever experienced before, not refreshing or cleansing at all, just endless sickness. The musculr contractions were so violent that I thought I was going to damage my ribcage.