Hello LM, welcome to the forum. Sorry to hear you are having problems with VA, you'll find plenty of experience here!
It's early days with the Ovestin, and all the local oestrogen products can take a while to work. If you don't feel you can persevere, there are other products available. I don't know what you have in Australia, but here there is another cream, generic Estriol, but it is weeker than Ovestin and you have to use more. Vagifem is a small pessary and you might get on better with that. There is also the Estring, a vaginal delivery system which stays in place for up to 12 weeks.
As to the headaches and nausea, it is more likely to be the stress of the condition itself, as all the targeted VA treatments are extremely low dose and there wouldn't be any systemic absorption.
Replens is not recommended, full of chemical irritants. You want a moisturiser that is natural and with as few ingredients as possible. You have a good one in Australia called Olive & Bee, just contains olive oil and beeswax. The UK's Yes products are also very good, as is the American Vmagic. The Yes products are pH matched to the vulva and vagina, which can help prevent BV and thrush. You can find all these online.
In the meantime, don't use anything but plain water to wash the area, as soap, shower gel, etc can irritate.
Have you been offered any systemic HRT? As you have no uterus it is just a question of replacing the oestrogen you are no longer producing if your ovaries have packed in. This would help all your symptoms and protect your heart and bones for the future.
Best wishes,
JP x
