Have you gone through a nasal endoscopy? Without x-ray or CT scan, you can't be sure it's not sinusitis. In chronic sinusitis, nasal discharge is not always observed.
It could be a migraine problem or tension headache. It could be a sign of depression, other mental or neurological disorder and of course it could be meningitis as well.
A doctor's advice is necessary and I guess he will ask for a CT Scan image of the brain and para nasal sinuses.
Before I forget about the fever, I think it's a bacterial fever. Since it has been 5 days that you have got the fever, it's probably not a viral infection. There is definitely an infection somewhere in your body. The immune system is responding by increasing the body temperature to kill the virus or bacteria that has caused the infection. As soon as you find a cure for the infection, fever will disappear. Without diagnosis, it's difficult to tell for anyone where you have an infection.
Good luck!