They're pretty sure I get a (mild but still horrid) form of cluster migraines. I've had one silent migraine (during puberty and I ended up losing all vision in the center, like opposite tunnel vision) and then only a few "classic" migraines, usually associated with different illnesses (Lyme and mono, both within the last few years). I'd take that kind over the cluster, though.* The only nice thing about the clusters is I know they'll happen in late September until early November, and they start between 5 and 6pm every time, and they only last 4-6 hours. While they last though, what exquisite pain. It's like all of the pain from the full day-long migraine mushed into a few hours and one side of my head. My right eye starts tearing up horribly and swells up until the headache diminishes. Medicine doesn't help. When I feel the tightness in my head along the right side that means one is coming on, I take max doses of ibuprofen and Tylenol before pain-induced nausea sets in. Once the pain proper starts, I take Benadryl until I fall asleep. The amount of time Benadryl knocks me out for is about the length of a standard cluster migraine. If I can't take Benadryl and sleep, for whatever reason, I'm usually reduced to a moaning puddle of human until it stops, crying from the eye all the while. I absolutely can't function in the depths of one of these, and if life-threatening situations loomed I might just let it happen. I know they'll end shortly, but each time they start I want to die just to end it. I also will rig an eye patch that puts pressure back on my eye and socket, which seems to help.
I didn't start getting these until a few years ago. Given the seasonal nature, we first thought they were just allergies. I thought the first year was bad, but the second year made the first look like a cakewalk. Luckily they haven't gotten worse since then, but it ticked enough boxes that, despite the fact that women usually don't get clusters, my doctor is pretty certain that's what's going on. I only get 3-4 a year, though, which is really getting off easy with these. I don't know if that's related to the fact that this type of migraine seems to hit men more and worse, or if I just got lucky. Given that, we don't treat them with the oxygen or anything else a more chronic sufferer would need. Also, since antihistamines knock me out very soundly with only a normal dose, I just take a normal to slightly high (but not dangerous) dose and it doesn't fix the pain but it does put me to sleep. I did realize last year that I spend all of fall in a state of mild dread waiting for that tell-tale tightness. It's very distinct, feels like my head is in a vice but with no pain, and very much only on the right side of my head. After 30-60 minutes of that, the headache strikes. The best description I've seen for a cluster headache was actually an image of a tiny demon trying to rip someone's eye out or tunnel behind the eye into the skull, and it's a perfect way to explain what I feel when I get these.
*I'm not saying clusters are worse than other forms of migraines in general. Just that, for me and the way they present, the pain in a cluster migraine is much more intense than the more usual variety. My mom's had chronic non-cluster migraines for years and I think I would keep my clusters over her migraines, if I had to pick.