Probability that you have Cluster but there are a number of conditions which mimic Cluster and which are rathe serious. Hence, need for a skilled doc to sort thru the jumble--headache specialist being the best bet in terms of knowledge/skill/experience.
Stress may a trigger for some but is not the cause. Core issue is a jumble in our hypothalamus--nothing which be cured at this state of knowledge. So, good mix of appropriate meds/other treatments will give a high chance of good control.
Learning about them is a primary protection. Explore the buttons, left, starting with the OUCH site. Then,
Cluster headache.
From: Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

or

(Orphanet Journal of Rare Diseases)
[Easy to read; one of the better overview articles I've seen. Suggest printing the full length article--link, line above--if you are serious about keeping a good medical library on the subject.]
Leroux E, Ducros A.
ABSTRACT: Cluster headache (CH) is a primary headache disease characterized by recurrent short-lasting attacks (15 to 180 minutes) of excruciating unilateral periorbital pain accompanied by ipsilateral autonomic signs (lacrimation, nasal congestion, ptosis, miosis, lid edema, redness of the eye). It affects young adults, predominantly males. Prevalence is estimated at 0.5-1.0/1,000. CH has a circannual and circadian periodicity, attacks being clustered (hence the name) in bouts that can occur during specific months of the year. ALCOHOL IS THE ONLY DIETARY TRIGGER OF CH, STRONG ODORS (MAINLY SOLVENTS AND CIGARETTE SMOKE) AND NAPPING MAY ALSO TRIGGER CH ATTACKS. During bouts, attacks may happen at precise hours, especially during the night. During the attacks, patients tend to be restless. CH may be episodic or chronic, depending on the presence of remission periods. CH IS ASSOCIATED WITH TRIGEMINOVASCULAR ACTIVATION AND NEUROENDOCRINE AND VEGETATIVE DISTURBANCES, HOWEVER, THE PRECISE CAUSATIVE MECHANISMS REMAIN UNKNOWN. Involvement of the hypothalamus (a structure regulating endocrine function and sleep-wake rhythms) has been confirmed, explaining, at least in part, the cyclic aspects of CH. The disease is familial in about 10% of cases. Genetic factors play a role in CH susceptibility, and a causative role has been suggested for the hypocretin receptor gene. Diagnosis is clinical. Differential diagnoses include other primary headache diseases such as migraine, paroxysmal hemicrania and SUNCT syndrome. At present, there is no curative treatment. There are efficient treatments to shorten the painful attacks (acute treatments) and to reduce the number of daily attacks (prophylactic treatments). Acute treatment is based on subcutaneous administration of sumatriptan and high-flow oxygen. Verapamil, lithium, methysergide, prednisone, greater occipital nerve blocks and topiramate may be used for prophylaxis. In refractory cases, deep-brain stimulation of the hypothalamus and greater occipital nerve stimulators have been tried in experimental settings.THE DISEASE COURSE OVER A LIFETIME IS UNPREDICTABLE. Some patients have only one period of attacks, while in others the disease evolves from episodic to chronic form.
PMID: 18651939 [PubMed]
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Print the PDF file, below. These are the most commonly used meds for Cluster, along the evaluation of effectivenss. Use it as a tool to discuss options with the doc. If he isn't working from this group, need to reconsider his skill.
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You can print out relevant sections from this pub, written by one of the better headace docs in the U.S.
Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

or

ALL NEW!! HEADACHE 2010-2011
Robbins Headache Clinic
Free, 50-page. Covers all major headache Dx and
related issues.
In a PDF file.
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Avoid OTC pain meds (you experienced the limited knowledge of the ER doc---all too common there.) Pain meds will not relieve and, with much use, will increase frequency of attacks. TOTALLY avoid alcohol as long as you are having this kind of headache; avoid solvents and potent cleaning agents--they will trigger Clusters for many, especially alcohol.
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