I do not know much about migraines but I do know that erratic estrogen and falling estrogen levels cause severe headaches. A good book to read on this is Elizabeth Vliet's book: Screaming to Be Heard: Hormonal Connections Women Make and Doctors Ignore. She has a section on migraines and headaches, if I remember correctly.
Do not, I stress do not, let any doctor talk you into having your ovaries removed (unless there is a cancer of course) . Preserve them as long as you can. Don't !!
Good Luck
KKay