Sorry I can't recommend a specific medication, since pretty much all of them have failed for me. However, even though you don't get migraines frequently, it's always best to make sure you have your medication with you at all times. You never know when something may trigger a migraine. Case in point, if you are not at home and are driving somewhere out on a highway or in traffic, getting a migraine can seriously impair your ability to drive safely. Yes, you can pull off the road, but you don't want to get stranded out somewhere when your level of pain is bound to increase. I used to have a job that required a tremendous amount of travel, in the days before abortive medications were readily available. I can tell you, trying to drive in intense pain is not a good thing. I can identify locations on practically every highway and interstate on the east coast where I've had to pull off the road and puke my guts out, and had no choice but to keep driving until I got to my destination. It's misery that no person should have to live with even on an occasional basis.
I hope you can find a medication that will help you, and please make the effort to keep it with you at all times. I guarantee there will be a time that you will be thankful for it.
Best of luck,