i am goin thru the same exact thing... i had my period on march 31st and i had unprotected sex around the 10th which is during the time i ovulated. i went to the doctor today and they said you shouldn't test until about a week after your missed period but they told me that i have a 99% chance of being pregnant if i'm not on birth control (which i'm not). i am going to try a hpt tonight but i'm afraid it will give me a false negative. i am going to go back to the doctor in 2 weeks to find out for sure if i'm pregnant or not. you should wait until you've missed your period unless your like me and cant stand waiting, then you can try a hpme pregnancy test anytime since your period should be about 5 days from now which is when most tests can come back positive. i hope this helps! =) good luck!!
Here's the 2 weeks 4 weeks thing. The average woman has a 28 day cycle and ovulates on cycle day 14. She becomes pregnant on cycle day 14-15 and finds out she is pregnant on cycle day 29 when her period does not come. Since some doctors calculate pregnancy from the last menstrual period, that adds two additional weeks to the time the woman has actually been pregnant (since ovulation) when she misses a period. So if you are counting how long you have really been pregnant, it is actually just about 2 weeks, or since you ovulated, however your doctor may add an additional 2 weeks to that (which I consider imaginary weeks) by counting back to the first day of your last menstrual period (cycle day 1). Since sperm can survive in the body for about 4 days (but up to 6) you could be pregnant. You had sex on cycle day 12 if the 27th was the first day of your last period, which puts you right in the fertile zone for an average woman. Since you don't seem to know when you ovulate, and it's too late for the morning after pill if you don't want a baby, you should just wait to see if your period shows. If you want early results you can try an early result test, but remember because every pregnancy generates hcg at its own rate, the early tests are not accurate for everyone. The only sure test is one taken after your period is late.