Unfortunately narcotics (I'm assuming this is what you're weaning off of) can be a difficult choice for migraine sufferers. I understand your concern about faout falling asleep and being out of control. I have had similar experiences. I take narcotics on a regular basis and when I have taken too high a dosage find myself falling asleep.
I always remember something my neurologist said to me, don't put off getting relief of your pain. It's okay to take the necessary medication to fix your migraines. I finally got relief yesterday from a migraine I had been suffering from for 3 weeks. I was at the point that I would do anything to stop the pain.
I am often concerned about how much medication I am taking but I also know that I am responsible about what I take. The fact that it bothers you that you fall asleep demonstrates that you're not headed for an addiction. People in pain generally only take medication when they're in pain. And you deserve not to be in pain.
On a separate note, could your doctor write a note to your insurance saying that the quantity you need of Relplax is medically necessary?
I hope you feel better soon and find a solution that works.
Best of luck.