I have had bronchitus for three months and it won't go away! Two rounds of antibiotics, what now?

Get X-ray. If you haven't had a chest x-ray, get one. It could be something else. It might be a sinus infection, needing different medicine, or maybe allergies which won't benefit from antibiotics. Please go back to your doctor.
Do you smoke? If you smoke, you may have chronic bronchitis, the treatment for that would require smoking cessation. You might have asthma too. If you haven't been given, a short course of oral steroid and short acting bronchodilator inhaler might help. You may need more workup, like pulmonary function tests. You need to get a correct diagnosis. Talk to your doctor, and possibly get a pulmonologist referral.