I only took one Levaquin 500 mg pill (prescribed for bronchitis) ...

I only took one Levaquin 500 mg pill (prescribed for bronchitis) and got horribly sick. I was so dizzy I nearly fell when I tried to walk. I went back and forth from blazing hot and sweating to freezing and shivering. My hands and feet were numb and tingling. I had diarrhea. Worst of all, I could barely breathe, felt like my lungs were too tiny to get any air. Finally got back to nearly normal with Benadryl. However, it's now 3 days after I took the single Levaquin pill and I still have tingling and numbness in one ankle and calf. I am horrified to see how many other people are having severe reactions to this drug, and I want to know WHY IS THIS POISONOUS DRUG STILL ON THE MARKET?