Hello - This may sound wacky, but it worked for me. For around 15 years I suffered migraines at least monthly, usually related to my cycle. I'd feel sick and headachy and have to go to bed for the whole day.
I started singing lessons a year ago, and my singing teacher said that my tongue was very 'knotted'. The tongue is a very big muscle, apparently, a lot bigger than what we are aware of, and my tongue muscles going back into my head were very tense. He gave me exercises to free it up, and I as did them my migraines stopped. Might be coincidence, but I thought it worth sharing in case it's not.
What you do: extend your tongue as far as possible into your right cheek. Slowly move it down between your teeth and your gums, then into the left cheek, then up to the top between teeth and gums and back to the right cheek, so that you've done a whole circle - which takes about 4 seconds. Always extend your tongue as far as you can. Do 8 continuous circles clockwise - then 8 anti-clockwise; then do 6 each way, then 4, then 2. It's quite painful / tiring, specially at first, so don't overdo it or force yourself - have a rest between cycles. He said once a day, but sometimes I do it more often than this, or do a cycle or two if I feel tension building up.
Best of luck, and I'll be interested to read your feedback.