Foods for PMS nausea?

This is the first time I've felt nauseous before my period but I'm due on and felt like vomiting since yesterday, especially in the mornings around 10:00-12:00

I don't know what to eat to settle my stomach, I tried salty crips which used to work with travel sickness for me but the oil made me feel worse. I've put a sweet potato in the microwave because I read that starchy foods help but I have no idea what actually works.

What do you eat? What do you find works?

(+I'm definitely not pregnant before someone suggests that)