Hi,
Strange smell that is enhanced is possible during some stage of any
rhinitis. be it flu or anything. With your detailed history of
back pain, pain in eyes, mild
diarrhea, coughing, nausea and weakness are surely indicative of viral infection. It is possible to have secondary bacterial infection that can cause sinusitis and thus the altered smell.
I would advise you to consult an ENT surgeon for nasal
endoscopy to know whether there is just rhinitis, any mucopurulent discharge, congestion and so on. This will give an idea about the present status. Do a CT scan of sinuses to know the status of sinusitis and relevant tests of blood. All these will give an appropriate diagnosis and thus allow any additional treatment such as antibiotics, anti-inflammatory medicine, decongestants.
Chronic sinusitis will need surgery after a course of the above medicines. Take nasal decongestant drops and steam inhalation.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. T. Chandrakant, General Surgeon