About a year ago I began having a monthly migraine. It feels like it's a sinus headache but I have no sinus congestion etc. I'm post-menopausal by several years so I don't think it has anything to do with hormones. I used to think it had to do with eating something with sugar or salt for dinner or late in the evening, but there are plenty of times I do that and don't get a headache. I'm beginning to think it has something to do with barometric pressure. Thanks