I have this - go to the doctor and ask for Migraleve - if taken early enough it helps. It might be available over the counter actually...not sure. I was also given co-codamol which is a prescription painkiller, but it wasn't particularly helpful. There's another migraine painkiller which apparently works well, Sumatrip I think it's called. I have this but haven't tried it yet.
Focal migraine's happen when the bloodflow to the brain is reduced (I often lie over the edge of the bed for about an hour to combat this) which causes the aura (the 'flicky lights' in your vision as my doctor calls it.)
Then a headache comes on for a few to 24 hours, often with nausea.
Also remember when taking medication, if it sometimes doesn't work this is because the metabolism slows during a migraine attack. I take caffeine and drink lots of Coke which helps a lot. When I'm out and without meds, if I feel a migraine coming on I down a bottle of Coke as the glucose combats nausea. I got made to do this by a piercer when I mentioned that I get migraines and often feel faint when getting pierced last time I got an earring done.
For some people certain foods or conditions affect or trigger their migraines, for me it's a monthly girly hormone thing haha. But good luck with it, I can sympathise, it's not a nice thing to have to put up with.