It can get bad, don't ever ignore it. I am the worlds worst about saying "it will pass, I don't need a doctor". About 20 years ago I developed pnumonia from a cold and bronchitus. Didn't realize it till started coughing up blood streaked white foam. When I got to the doctor my O2 saturation was 70 percent. They immediately admited me to the hospital for 10 days of IV antibiotics, oxygen, and breathing treatments. Even after discharge it was 6 weeks before I regained all my energy.