Nausea and vomiting after sex

I'm 14 weeks and 2 days and lately after sex I feel very nauseated and even vomit. No pain and it usually goo away after 10 to 15 mins. My fiance and I don't necessarily have "rough sex" but it's not always "nice and slow" lovemaking either. I hope we're not harming our baby. I just recently got back my desire to have sex more than about once a week. Has any mommies to be experienced any of these symptoms after sex?? I would love to know you ladies stories.