Cluster headaches are a symptom and not a cause or source of the problem. I am assuming you eliminated any potential causes and are now just treating the symptoms.
Are you looking into diet, exercise, room lighting, time outdoors with quality sunlight, sleep habits and quality of sleep, adverse effects of other medications, blood pressure, thyroid, heart and heart beat irregularities, etc...
No need to elaborate, I just want to make make sure your doctor is doing everything to ensure your success in addressing your health concerns.