Hey lovely - i got them all the time when i was preggers with number 3- I also got them really badly after I delivered- everytime he dropped or gained a feed- i would get one- damn hormones. I ended up going on Beta Blockers and they have been a godsend- I am still on them now as they take away the reactions my body goes under when my hormones fluctuate. They have been life threatening. Apparently they are a common treatment for migranes esp when preggers as they are safe to take. Speak to your health care provider about this option.
HTH and hang in there!!!