Long flight with all day nausea. Tips?

I'm about six weeks now and will be flying for 9 hours on Friday. Just today I started with nausea all day but still have not gotten sick. I am used to only have it every once in a while but today it was all day. Any tips on how to curb it while on the plane or things to bring just in case I do get sick. I know I need to get up and walk while on the plane but my fear is I'm gonna get sick when I have to keep my seatbelt on 😁