welcome to HealthcareMagic
You did not mention that you were having sex continuously during this month so it is not fair for us to mention about the sex & pregnancy
because it can offend you.But now since you said it please understand that nausea;vomiting;sick feeling;giddiness;breast tenderness are few signs .Please go & get a pregnancy test done then if it is positive then consult a doctor for further what ever you need to do & if it is negative then you can go ahead with antacid
& medicines for vomiting.Since we are not face to face we can only advise you as per the symptom & complaint you post on this site.
We are here to help you