Vagifem pessaries are the strongest of the estrogens, so maybe that was the problem for you..
Useful info i saved ( not written by me by the way)
Ovestin is Estriol .. Gynest is Estriol..
The three estrogens: estradiol, estrone, estriol
There are three common forms of the hormone we call "estrogen" (and many many lesser variations and subvarieties). Understanding what each one is and does can be helpful in deciding which one(s) to supplement with when planning HRT.
Estradiol is the major estrogen produced by ovaries and is the strongest (the most effect for the least quantity) form.
Estradiol is the "active" estrogen—the one that is capable of the fullest range of estrogen effects because it is the one that actually goes out there in our tissues and sockets into estrogen receptors and causes estrogen effects. In addition to being made by ovaries, it can also be produced by conversion from a number of precursors in the adrenal glands. It requires certain nutrients at specific levels to be metabolized properly, and it requires certain other factors to be present to determine which metabolites (some of which are considered more desirable than others) it is broken down into.
Estrone is considered a weaker form of estrogen. It is typically produced by special belly fat cells, and is the major estrogenic form found in naturally-menopausal women who are not taking HRT. It is not directly active in as many tissues was estradiol is, but can be readily converted by to estradiol for actual use. Because of this, it is considered by biochemists to more properly be thought of as an estradiol precursor (although the conversion can go both ways, meaning that estrone can also be considered a breakdown or even a storage form of estrogen). It is sometimes considered "safer" than estradiol by virtue of its weakness, but since larger quantities are required to get the same effects as a smaller quantity of estradiol as well as the fact that it is normally converted to estradiol when that form is needed, other sources consider it no more or less safe than estradiol.
Estriol is a metabolic waste product of estradiol metabolism that can still have some effects upon a limited number of estrogen receptors. It is formed in the liver and is 8% as potent as estradiol and 14% as potent as estrone. Once estriol is bound to an estrogen receptor, it blocks the stronger estradiol from acting there. Thus it is considered to have both estrogenic and antiestrogenic actions.
There is also some evidence that, because it is so weak and blocks the stronger forms, estriol can be considered to have "anti-cancer" action.
To take it in quantities adequate to have effects comparable to estradiol (that is, to occupy as many receptors as a needs-meeting level of estradiol), however, the risk rises to the same level with estriol as with estradiol.
A particular breakdown product of estriol, 16-hydroxyestrone, is elevated in women receiving oral estriol and is associated with an increased risk of breast and cervical cancers. Estriol has also been implicated as a source of interference in lab tests for estradiol, leading to "clinically significant" testing errors. It is believed to have special efficacy for genitourinary tissues and skin generally, but that is poorly studied and results of existing research are not conclusive.