Hi Kayte B,
It sounds like your getting migraines associated with an hormone imbalance, seeing it come at the same time as your PMS.
Go to Migraine-Headaches-Information.com
and read what they have got to say as this really helped me get rid of severe migraines. Mine would last 3-5 days also and it didn't matter what medication I took, the migraine would just come back again after the 4 hrs of the meds working and seemed to never go away.
I had vomiting, sensitive to light, sounds, I just seemed sensitive to everything all the time, it was horrible. I usually always had to get injections at the drs or hospital to get rid of them. This site helps about 85% of women with migraines.
Can you believe it I don't get them anymore at all. Yehhhhh!! After two weeks taking the natural progesterone capsules I didn't have anymore headaches, it was amazing! At the time I thought I would never get a cure. You need to go through them as they make it up a certain way to be identical to your body.(not synthetic)
So please try it, because I know how much they just take over your life. I still have problems with a bad back which I get chronic pain with, but at least I have got rid of the extreme head pain.