Hi my2boys99
What have your periods been doing - are they irregular? If so I agree with Dancinggirl and you need HRT as well as Vagifem to help protect heart and bones, at your young age.
Re Vagifem absorption. If your body is lacking in oestrogen and you have vaginal atrophy and associated bladder problems - then your tissues will already be very thin. In situations like this, when you first use the Vagifem, a little oestrogen will be absorbed into the system but hardly any and I doubt it would be noticeable unless you were post-menopausal and not used to oestrogen at all. Once you have used it every day for at least 14 days (maybe more if atrophy is severe) the tissues gradually thicken up so almost none is absorbed - so little that not even progestogen is needed to protect the womb lining.
I presume you are not in UK as we don't have estrace here so not sure what it does and whether it is a form of vaginal oestrogen?
Headaches are listed as a common side effect (between 1 in 10 and 1 in 100 women reported them from a trial) from Vagifem but the product info states that if present this would be most likely at the beginning of treatment - hence the importance to keep going as Dancinggirl says - until you're through it and you should be fine!
Hurdity x