How is your diet over-all?
When I suffered severe PMT (1990s) my worst symptom was sudden onset of nausea to the point that I had to look for a waste bin/bucket/drain 'in case' though I was never actually sick. I was advised by NAPS that it was probably due to a sudden drop of blood sugar when the body became hungry due to hormone upheaval - it was always 10-14 days B4 each period. I was told to eat every 3 hours, 24/7 - even in the night. Not to eat more but to spread my meals through-out the day.
To this day I carry emergency food: dried fruits and nuts, bananas, ginger biscuits : to stop that dip. As a recovering anorexic I cannot allow my body to become hungry so I try to eat B4 it feels it needs an energy boost.
Dry toast. Ginger biscuits. Ginger tea or chopped small to chew. Dried fruits. Nuts. Boiled rice, cooled. Pancakes are a good standby, the mix can be kept in the fridge for a couple of days and used immediately. A hot cup of
Bovril with toast. The idea being is to keep the stomach working to avoid that lurch.
Dextrose tablets can also help, advised by the Ramblers Group and I carry them everywhere. When my blood sugar is low and I chew one, they fizz
. Keeping hydrated is important too.