Hi thanks for contacting HCM.... You had viral flu of respiratory tract.... But here after that you developed bacterial infection secondary to viral.... It could be bronchitis like condition that can lead blood in sputum... You might having excess cough and overeffort can lead irritation and blood in sputum... Don t self medicate.... It is better to use levofloxacin like broad spectrum antibiotic.... More water taken.... Steam inhalation also useful for cough drainage.... If needed and congestive symptom more then antihistaminic drug given... Your respi examination done by auscultation ...If crepitation feeled then chest x ray done for rule out pneumonia... Take care... Dr.Parth