I posted about this last week as I have had that question for the last 10 years too!
The pattern that I am seeing is a build up to last period and then a build down (potentially of a similar time-frame but that’s just my theory) - however, this can take months for some and years for others.
I think that us that suffer the dreaded nausea have a more turbulent experience which is linked to over stimulation from the only hormone that does that - oestrogen. HRT cannot help us as we are then adding to the oestrogen load. The combined pill, very high estradiol, or the POP that suppresses the cycle, may help some by overwhelming the hormones so that our own (and the volatility) hibernates in trying to redress the balance. Progesterone cream is also good for cushioning the oestrogen spikes, we have silly amounts of it when younger and then it dwindles from about age 35 until there’s barely any left 10 years later. However, oestrogen spikes can be gentle one minute and then like a tidal wave - which is a good analogy of the sea-sickness we feel too!
You could try some of the above suppression methods or wait it out. Beyond that, there isn’t much we can do as all the support out there is aimed at replenishing oestrogen but that’s of no help until it actually falls.
One day though. It will stop. Just hold on tight.