What Causes Breathing Difficulty And Chest Pain While Suffering From Bronchitis?

I went to the walk in yesterday and they said I have Bronchitis. They gave me an antibiotic called Clarithromycin but everytime I take them I feel really heavy breathing almost like im about to faint from all this light-headedness. The fact the pills are not doing anything leads me to believe that I might not have Bronchitis, maybe something more...serious? I have never experienced anything like this and it worries me. I also have not ate or slept properly in 3 days and its taking a toll on my body. My symptoms are; Breathing problems in chest/chest pains Mucus/phlegm (Green/yellow,sometimes blood) Hot cold sweats in middle of night Sore throat Heavy cough Also, Yesterday I had vomitted after taking these anti biotics