When is the nausea/vomiting stage over while pregnant ?

Depends. : For many women, this passes after the first trimester (12 weeks). A few unfortunates struggle throughout.

1st trimester: The first trimester (first 1-3 months) are the most common months to have the feeling of nauseousness. On rare occasions it can be severe (hyperemesis gravidarum) and require rx meds or even an iv. But usually by the 2nd and third trimester the feeling subside. Good luck.