I also get nausea a few days before my period, which continues until the bleed is finished. Truelly awful and disturbing! These few months I also get diarrhea for a day or two - oh the fun! I have never been nauseaus around periods before so it must be perimeno.
Row ginger helps me the most, also anything with ginger - buiscits, tea, or foods with bitter taste! Small bites of dry food every now snd then throughout the day also helps. Strangely, drinking tonic (no gin:) in small sips helps a lot - it must be the bitter taste I guess.
All in all it passes to reappear again a month later ! I trully hate it!
Milamam