You're sitting there doing nothing in particular, getting on with your day, and suddenly this THING, this cloud, this physical wave of stuff, sweeps over you, like a great bag of invisible slime just burst over your head for no damn reason and you feel like you want to curl up under a duvet with a fuckton of chocolate and perhaps a Sad Keanu photo and just listen to The Smiths till you die of angst and emo.
And, yes, your conscious mind knows all the time that there's absolutely no reason to think your life has suddenly turned to shit, and eating a fuckton of chocolate (and, yes, that IS a legitimate measurement of quantity) will not, in fact, make you feel better but it might make you feel something, something that isn't "you are a worthless human being and your entire life is utterly meaningless". And you know, from experience with mood swings and periods, that this kind of hormonal suck is time limited and you should just go easy on yourself for a few hours or a few days and you'll get through it.
And, yes, part of you is still saying that your conscious mind can just shut the fuck up and leave you alone. Sometimes there isn't enough chocolate in the world. But it gets better.
The menopausal version is more vicious than that, because you know - you know - that it's not the period induced mood swing. You knew those would go away, because you had them rhythmically, they were reliably time limited. And you know for, ahem, obvious reasons, that this isn't that. So while your conscious mind is being all sensible and saying to you, hey, it's just that thing again, you know, the thing with the fuckton of chocolate and the inappropriate listening to The Smiths and crying at Bujold fanfic, the bit of you that never bought it even when it was actually true is waving a little flag and going "how do you know".
This time. How do you know it will stop? How do you know it will ever stop?
Um... rational thought suggests because if it didn't all revolutions would be led by homicidal middle aged women alternately crying into a bag of twirl bites and screaming obscenities & waving chain-saws at people who jumped the queue at bus stops. The dearth of chain-saw-wielding harridans (because I checked. Well, I googled. Honest) is one of the few things that reassures me. This, too, will pass.
And, oh goodness, now i-tunes shuffle is playing me Karma Police and I have to go find some chocolate right now.