HI, thanks for using healthcare magic
If the symptoms have been ongoing for this length of time then it is not likely a
cold but may be
rhinitis (inflammation of the nose) and
sinusitis (inflammation of the
sinuses).
These often exist together.
Most often due to allergies. Allergies can be related to any food, drink, medication, dust, pollen, animal dander etc
Treatment would involve avoiding the allergen if it is known, the use of anti histamine/decongestants medications (these are over the counter).
If you can identify the cause, this would be best,
allergy tests, done by your doctor, would help with this.
You can ask your pharmacist for an antihistamine/decongestant combination of medication.
I hope this helps