Hey Crispy. It's possible that it's not related to ovulation and your hormones are just a bit skewed because of the HRT - I also had the same thing when I tried it for a few days only, my period was about 7 days late i think (which never happens). What I've come to realise through my current experience with Zoely is that for whatever reason, in my early 40s I have become super sensitive to Estrogen changes, and it sounds like a similar thing with you too maybe.
In the last 3 days I've had the return of my crazy bad night sweats which I think causes my insomnia (both in waking up and then unable to get back to sleep, as my core body temperature has risen). It's definitely not been as severe, or if it has I've so far been able to cope so much better with it the next day (which could also be due to me increasing my SSRI). The return of the night sweats/sleep issue has also been accompanied by my boobs dropping from the super swollen and painful state they were in from about day 5 to to day 18 of taking Zoely (which is my classic very high estrogen indicator), down to still being a larger cup size but not swollen or painful at all anymore. These two things happening in tandem has showed me that the night sweats and insomnia must be related to when my estrogen levels drop. And as I mentioned before my Estrogen level doesn't even have to be clinically low to cause me problems... a drop of any kind causes it, even when going from "super high" to "high".
I've also had a lot of breakthrough bleeding over the last 4-5 days - almost like my normal period - but I can deal with that.
Your symptoms are different from mine but it would make sense to me that it's down to changes in your hormone levels caused by the stopping of HRT and my own experience is that estrogen is the pest!! But I'm obviously just guessing
As all the literature I've poured over says it takes 3 months for full suppression of your own natural hormones on birth control pill I'm hoping that when that happens it will stop my fluctuations which cause these symptoms for me.
Side note: still annoyed that the hormone specialist told me (1) my symptoms "can't" be related to my hormones when they so clearly are, (2) hormones fluctuate all the time in your natural cycle so this wouldn't cause you problems and (2) she gave me incorrect info about my hormone levels - she got the prog and estrogen results the wrong way around
Hope you start to feel better soon Crispy - I know it's hard if you're experiencing rubbish side effects but I'd really recommend trying to stick with a contraception pill for a full 3 months once you start it if you can, as I think only then can we judge if it's working or not xxxx