Hi there
I have had exactly your experience and have been on Lucrin (in same family as Zoladex) to suppress my ovulatory cycle. You are absolutely right in that Zoladex does wipe out your own (endogenous) production of estrogen (and progesterone/testosterone) but the idea is that you "add-back" hormones in a stable form, so whatever HRT regime you are currently on. It sounds as if, like me, it is the fluctuations following ovulation that you are very sensitive to - and so Zoladex is designed to suppress these disabling fluctuations. Overall, I am better on than off, Lucrin - I had a short period without Lucrin to see if I could do without but the time around ovulation almost toppled me (very bad anxiety/depression) so have had to go back on it. To be honest, it's still not perfect - (I am on 150 transdermal oestrogen patch), I find I am functioning pretty well when I have low stress in my life, but when I get busy and have lots on (including positive events), I have the sense that my estrogen levels are readily depleted. So the regime requires you to be pretty self-aware. For some women, this regime can be great so it sounds like it could be worth a try. Or the tibolone which I haven't yet tried - but might in due course!
Best of luck!