Dr. Hanif warmly Welcomes you! Thanks for consulting me at virtual clinic. I have carefully worked through your case, and I can realize your health worries. Being your physician, I assure you not to worry as I will take care all of your medical concerns.   It is very less likely that you are pregnant. Only one day period cycle seems to be due to emotional disturbance only. Nothing serious I think. Its all because you had some bad experience of nausea, that is making you upset. Just to calm you down, you may do a pregnancy test done. That will give you a sigh of relief but it should come negative having said that you had sexual intercourse very close to menstrual cycle. If you need further, detailed and quick assistance related to any health issues, feel free to ask me a question directly from my profile. You can also attach Lab reports and pictures with direct question. Have a wonderful time ahead. Please don t forget to give your valuable feedback and five star rating, to help me assist you always in a better way. Click at Thanks & I Find This Answer Helpful too. Please, write a review on my profile, about your experience with me.   Regards! DR. MUHAMMAD M. HANIF PHILADELPHIA, USA