Fred - my husband has MS but does not suffer migraines. HOWEVER - that being said, I do not have MS and I have had a migraine for around 5 days as well. Sometimes severe, sometimes just a throbbing. My doctor believes it to be weather related (he said he has seen about a 500% increase in people coming in for headache / migraine symptoms this summer.)
He has prescribed topamax for me, but I decided not to take it after reading some of the horror stories about it.
Instead, I've been taking 500mg magnesium nightly, B2 (riboflavin) nightly, and here's some other ideas that may/may not work for you (some people swear they work - some have worked for me sometimes, sometimes not.)
1. Drop of peppermint oil on thumb and hold to roof of your mouth for about 30 seconds.
2. Submerge hands and feet in hot/(as hot as you can stand) water, while placing a frozen bag of peas or veggies on nape of neck. This actually has worked for me at times.
Know that you are not alone. It can be that the weather this summer is affecting you as it is me and many others. Hope you find some relief soon.