What can I use for bronchitis if I don't have a doctor?

Many viral /will pas. Many episodes of bronchitis will self heal with proper hydration, rest and diet. Otc meds that help you thin your secretions, like robatussin can be helpful. Over time the cough may pass but could take a couple wks. A secondary infection of greater importance could develop.Focal chest pain, fever >101.5> 2days, prolonged dizziness, etc would prompt a visit to a local clinic.
Over the counter . Bronchitis is dry coughing episodes relieved by Benadryl (diphenhydramine) cough suppressant unless associated with bronchial asthma where inhaler is needed and further evaluated by your doctor.
Lack of insurance. Your local health dept should have a primary care clinic staffed with a nurse practitioner or a physician's assistant, and your local federally funded community care clinic also offers visits on a sliding scale based on your income.