I think that you are absolutely correct that the little bit of blood in your mucus was likely secondary to coughing a lot with an infection. It sounds like you have a bad case of a viral bronchitis, also known as a chest cold. This type of infection can cause a low grade fever (but not always), a cough with some sputum production, and a runny nose. If you cough a lot, sometimes you can break blood vessels in your bronchi (tubes in your lungs) which results in some bleeding. With that said, you should not ignore blood in your mucous, even if it is a small amount. If it were to continue, or if you were to develop fever and chills, then you would need to seek medical attention right away. This is because these could be signs that your infection has progressed into a pneumonia
. Something like a pneumonia needs treatment with antibiotics.
For these reasons you should schedule an appointment with your primary care physician
. After a thorough physical exam to see if you have any signs of pneumonia, your doctor
may decide to get a chest x-ray to look for a pneumonia. If pneumonia is not suspected, then your doctor can give you a prescription for a medication to help out your cough.