Migraine headaches may well become worse during peri-menopause and there is a new drug in the UK suitable to help symptoms.
How often were U using the 'estriol'? Give this new med a whirl, it if helps ease VA symptoms without triggering migraines then that has to help.
In the meantime ask why the migraines have increased? It mayB that U require an appt with a dedicated menopause clinic, is this something that the Gynae could arrange rather than via your GP? After all the Gynae will be gaining info too.
A dedicated menopause clinic may know more about hormonal migraines but your GP anyway should be referring you appropriately. let us know how you get on.