It's not unusual for infections in the sinuses to migrate to the lungs. When I was younger I was prone to bronchitis and it frequently began as nasal congestion. You'll probably need a course of something like zythromycin (a z pack).
It's a weeks worth of antibiotics and sometimes an additional course is required afterwards.
After you begin treatment, it's good to get light regular exercise, like walking or stretching with deep breathing, if you're strong enough to move about. The lymphatic system, the main pathway for our immune system, has no pump to move lymph, the fluid that carries the lymphocytes, phagocytes, and foreign material back to your circulatory system. Muscular movement contracts the lymph vessels and they have one way valves to move the lymph back toward the heart. It's difficult to recover from infection if you don't move about and circulate the lymph. This is part of the reason that older people are more likely to have prolonged or lethal infections. As we get older and feel less energetic, we don't exercise our bodies as much and our immune system is less effective.