Hi , as per your clinical history it appears as you are having Chronic rhino sinusitis. Most likely it is due extensive infection but you need to rule out other reason for blood stained post nasal drip . Here my suggestion is that you should consult your ENT doctor for thorough examination, Diagnostic nasal endoscopy and treatment. Meanwhile you can start steam Inhalation , saline nasal drop , mucolytic syp ,levocetirizine + Montelukast combination & antibiotic. Hope above information helpful to you , Regards - Dr KK ( Karade ) .