Dear Dragonfly. There is more than 1 type of migraine, and you could have different types, I was diagnosed with 5 different types; each has their specific "signature", however they can and do, switch sides from time to time. The worst I have are cluster headaches; they feel as if something is boring through my left eye. These are almost always left side, but from time to time it switches to the right.
When I have a bad one like you describe, it is normal for me to increase the amount of medication, and even add something to the mix. I have very explicit instructions on use and if I can't get it to stop after following this, I call and they'll normally create a cocktail of the meds I have to stop it. Afterwards, of course, I have the migraine hangover..it feels like your head is bruised and exhausted; that too is normal.
I was told, however, that whenever you have a new type of headache, a change from your normal pattern or an increase in the severity, to get in to my Dr., I would suggest the same for you.
Often, a Dr. can write a letter to the insurance company to get an exception to their formulary; I would find out about that too.