My recommendation is for a full ENT evaluation if your consulting physician believes it to be sinusitis. Primarily it can be treated by antibiotic administration once a culture and sensitivity of sinus tract aspirates(such as mucus) are investigated. Corticosteroid nasal sprays are also available to help reduce inflammation. A likely cause for chronic( long standing) sinusitis could be allergies(which would again be benefited by the corticosteroid nasal sprays) or due to deviated nasal septum or nasal polyps(which are growths that are seen). Headaches are commonly seen in chronic sinusitis patients and mood changes could be correlative to long time stress dealing with disorder. It could also be advisable to try some Over The Counter decongestants for allergies such as Pseudoephedrine(consult your pharmacist for brand values) Home treatments to improve sinus clearance will include using a humidifier in your house (dryness of the nasal passages predisposes to sinusitis). If the case is not responding to any medical treatment, nasal endoscopy, X-rays, CT/MRI or biopsy can be taken for evaluation of the cause. Surgical options are also available for medical resistant cases.