I am a 30 year old male who about 2 weeks ago was diagnosed with sinunitis for which i was prescribed steroids and amoxicillin. I still am on the amoxicillin but fear my sinus infection has turned into bronchitis. I have been sick altogether now for about 3 weeks and i feel like the amoxicillin is causing stomache cramps and lower back pain. What should i do? I am a smoker, but have cut back to less than half a pack of cigerates compared to what i was smoking which was over a pack a day. I am doing everything my doctor asked including trying to quit smoking, but to no relief of feeling sick. I don t know. I just feel like something isn t right, but could that be an effect of just being sick so long?