That feeling of wanting to vomit lasted me from week 6 to week 12. What really helped was medication from the gynae as well as motion sickness bands. Other than that, I made sure that whenever my stomach was empty, I filled it with some form of carbs like bread or biscuits, but I break it in bits to munch on and eat until I feel comfortable. For me, an empty stomach was a no no. Usually this gagging feeling is considered normal in the first tri. Hopefully you feel better by the second tri.
Fareena Ismail