Help! Meds are not helping my bronchitis!?

I am at my wits end here. I don't know what to do. I've had bronchitis for 2 months now. Been to the doctor tons of times. First, they gave me an antibiotic and an albuterol inhaler. When that didn't work, they tried a different antibiotic... Which didn't work. Then they tried prednisone, taken orally, and a steriod inhaler (ventolin). My doctor said since I have had irritated lungs for so long, they are "acting like" a person with asthma's lungs. ((I don't have asthma.)) But nothing is helping, not even mucinex. I'm only 20, generally healthy, and I've been bed ridden for days barely able to breathe. My lungs feel like they are running the mile and just want to give up and take a rest. Help, I want to be able to breathe again! I'm scared.