Unfortunately I have a high tolerance for pain, and I'm hard-headed, so I typically work through the pain. I have an office in the back where I can close the door, turn the fan on full-blast, and just get by. I can count on one had the number of times I've actually left work in seven years to sleep off a migraine.
I try to drink 3 to 4 quarts of water daily, which helps a lot. And a brief walk and stretching does wonders for me.
I hope you find a solution. Are you eating differently? Getting all your vitamins and minerals?