NNnn! nothing annoys me more than getting a migraine, and for over a year I've been getting them every few weeks. What a waste of time! 
I cannot tolerate being laid up unable to do anything, not even speak or move, or sleep properly, because of feeling sick & dizzy with a banging head. And as if that wasn't enough I even got a bout of labyrinthitis once on top of it all - someone up there's having a laugh. 
If anyone wants to compare notes, here's my appraisal of the blummin thing:
CAUSE: Who knows, different reasons for different people. For me it can be: being a passenger, drinking coffee, hormonal triggers, circular or swinging fairground rides (and kiddies' swings!). I also think it's hereditary - my dad gets them, and my maternal great-gran also got her "stars and stripes" as she called it every 3-4 weeks, same as I now do and from around the same age, too. 
SYMPTOMS: sharp pain on one side of head, ensuing nausea, dizziness, headaches, vertigo. Imagine a VERY bad hangover, so bad you can't stand up, coupled with sea sickness, that stays for 3-7 days. And every time you use your senses (hearing, seeing, speaking) it gets worse.
MANAGEMENT:
Medication - 1 Migard at onset does alleviate some of it, although if I take it too early it can cause nagging symptoms to just spread themselves out over a whole week. Better to lie down & take it at full manifest, then sleep it off, but I'm a parent so it's rare I get the chance to do that really.
Used to rely on Migraleve, but that doesn't seem to work any more for some reason.
Russell Brand had a migraine on the show he did from NY last week (I'd get one, too, if I had to travel all that way & then perform) - "give me 2 pink and 2 yellow, Matt, c'mon, you can't muck around with migraine"
Too true.
Food - Lots of water based drinks & nothing milky, sugary or alcoholic! I used to go on a strict regime of particular non-fat, non-sugar, non-rich etc regular plain meals, but I recently read that it is better to keep eating normally rather than be restrictive, so I do that - although I do stay off the chocolate when the migraine is phasing. And I rarely eat cheese or drink alcohol these days anyway. 
Fish has particularly good results, so I eat lots of that during a manifest, with plenty of vegetables. Yes, it is boring.
It's important to keep up the blood sugar, never skip meals, so I eat little and often. This works tremendously, but the downside is that I've put on a stone over the past year!
Lifestyle - Regular sleep is important, including for a nap 2-3pm when phasing. Luckily I can work from home, so the problems with looking at a VDU (which for any other employer would require me to take a week off work, and probably result in eventual dismissal for poor attendance) can be managed appropriately as I can still fulfill the requirements for my job without the pressure & stress of commuting & having to be somewhere 9-5.
PERSONAL: Migraine can put tremendous pressure on a relationship, and was a contributary factor to my divorce a long time ago. I am very lucky now (well, maybe it's my son who's the lucky one to have a dad that rallies round!) to have a supportive partner, even though he doesn't understand what migraine is and why it should be so debilitating (having never experienced the like). My son (5yrs) has come to understand that sometimes mummy has a headache and can only whisper to him. Bless him, the other day after school he said: "I'm going to get changed now mummy, but I won't turn my music up loud."
It's horrible on the days that we can't dance or play cricket together like usual. And my migraine causes emotional turbulence (often with depression, naturally), so imagine that feeling multiplied with a gutful of parental guilt! 
Well I guess that's cheered everyone up. 
lledeb
My symptoms are the same as you say, as for triggers, i have not managed to pin point a single thing and have had them for twenty plus years.
I drink coffee every day, so it cant be that or i would have one every day, and i eat a lot of cheese which they say could be a trigger.
I get no warning, one minute everything is fine, and then, wham! I cant see anything but flashing lights that distort my vision, and make work impossible.
The only cure is laying in a dark room for a couple of hours.