Thanks so much for the replies! Thats so comforting to hear your experiences.
I don't (knowingly) have PMDD but wondered if my experience fitted along those lines. I thankfully very very rarely have physical symptoms in my cycle (and then only very very slight). And this mental 'relief'/build up/absolute tantrum has only seemed to be at this heightened level infrequently, yet my cycle itself is fairly regular. So I am not sure how that works that symptoms might be so significantly different month on month. I have been trying to track my cycle for over 5 years trying to see if this is a pattern that 'fits' as an explanation but it really doesn't show up to me. So frustrating something so 'routine'/'regular' might not be at all.
Any further insights and experiences always welcome

Also anyone else find it kind of embarrassing not understanding their own cycle? I'm mid 30s and still barely making sense of any of it. That's near on 20 years of monthly 'cycles' that surely I would be familiar with by now. (Though maybe 2-3 years with various pills and 9 years of (3 x back-to-back) implants to mix it up too - but now nothing for 2+ years and although I'm more regular than ever, the symptoms just don't match up still either)

Made even worse if I encounter people (or content) where comments are thrown around like 'you will know your own body' or 'whats normal for you'. And even more embarrassment where someone much younger is all confident about their routine/cycle/affects etc, especially when I've tried tracking (including symptoms) and theres just too many variables for anything to add up. Chicken and egg/cause and effect - can never tell.