magz, welcome to MM.
I can really sympathise with you because I too started getting silent migraines (migraine aura without headache) once my oestrogel levels dropped. I didn't have migraines until I was menopausal.
From what you have said, it would appear that your migraines are caused by low oestrogen - before, during and just after a period are when they are at their lowest level. I also had migraines just before a period while I was still having them but to cut a very, very long story short, my migraines were caused by low oestrogen levels in conjunction with synthetic progesterone. I had a Mirena coil (contains synthetic progesterone) for contraceptive purposes and while I was producing enough of my own oestrogen and progesterone, I didn't have a problem but once my levels became too low, the synthetic progesterone become dominant and caused the migraines - synthetic progesterone changes the brain receptors.
Are you currently using any form of synthetic progesterone like the pill or a Mirena coil? If so, you could have a similar problem to me but if not, it could simply be that you need more oestrogen. A lot of pre-menopause women who suffer from menstral migraines use oestrogen in the lead up to their period.
I would recommend you use Oestrogel to keep your oestrogen levels up and avoid any synthetic progesterone. Your doctor might be able to prescribe Oestrogel only if you are still perimenopausal because you might not need any progesterone yet. How old are you and how far through the menopause are you?
I am now 55 and about 9 years post menopause so now I use 2 pumps of Oestrogel everyday (I split the dose by 12 hours to keep the levels stable) and 100mg of Utrogestan (a bio identical progesterone) vaginally every 5 weeks. I don't want to speak too soon but so far so good. For me, the important thing is to keep my oestrogen levels high and my progesterone use very, very low and never touch synthetic progesterone.
I sought the advice of hormone expert Professor John Studd and migraine expert Professor Anne MacGregor and it took me a very long time to get to where I am now and find the magic formula.
I hope that helps.