Sulfer drugs symptoms and conditions

I took Levaquin 750 for 10 days for a sinus infection. I took first 5 doses, went to see my doctor again 6 days later because I was still sick. She prescribed again 5 does of Levanquin 750. I am still coughing and I feel very tired. It did not help at all. I am still sick and I have muscle pains in my two calves and stress Achille tendon. I am a runner and I have sometimes problems with my calf: I have been not running too much recently and I was wondering how come suddenly I had those muscle pains in both my calves. I am not sure if it is related to Levaquin, but when I read all those comments, I am worried. Why I have been prescribed this antibiotics if it is obviously dangerous?

I would be interested to know how many of those who took Singulair needed to take antibiotics more frequently than they did before they took Singulair. I'll see the response then I will tell you why if it turns out that is a predictable side effect.