This is Dr. David. I am reviewing your question now and will be with you momentarily.
I am sorry you are having bad migraines.
there are other migraine headache medications like Topamax (topiramate) or Fioricet or rizatriptan which could help better than imitrex.
you may benefit from botox injections for migraines as well.
you need to ask to see a neurology expert doctor for migraines in the UK