### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
So I haven t found very much information on the subject, but from what I understand the situation I m about to explain is basically impossible. A week ago my boyfriend and I had sex and we didn t use a condom, he pulled out but I know the precum is often just as fertile as ejaculate. I was also on my period, but I ovulate the day after my period. I want to know what the chances are of me being pregnant. I m trying to decide whether or not I need to bring this issue to his attention and whether or not I need to worry. I m already feeling incredibly nauseous, though I have only thrown up once so far. I am also experiencing breast tenderness and fatigue. I know these are all three symptoms of pregnancy so I figured I should ask someone instead of just doing the generic web search. Thank you

### output:

Hello, and I hope I can help you today. Even though there is sperm present in pre-ejaculate, it is at a fraction of the amount that is present in the vagina after ejaculation.  Therefore, with Chat Doctor.  However, there is definitely a possibility of pregnancy if you had sex around your ovulation time, which is in your case occurs during your menstrual period. However, it takes a few weeks after conception for fertilized embryo to produce any level of hormone that would be high enough to produce pregnancy symptoms.  Pregnancy symptoms vary greatly between women, and many of the symptoms we commonly associate with pregnancy like nausea, bloating, breast tenderness, spotting, or mood changes can take place with PMS or other hormone irregularities as well as pregnancy. The stress of worrying about getting pregnant can also make women more acutely aware of the hormonal symptoms. Modern pregnancy tests are extremely accurate and will become positive within 10 days to two weeks after conception, so if enough time has gone by, I would recommend you perform a urine pregnancy test with your first morning sample according to the package directions. In the meantime, to summarize, no one can diagnose pregnancy based on physical symptoms. There is a possibility of pregnancy when you use with