conception issue?

[Msc83]

I am having a dilema...here is my story...i can't remember exactly when was my lmp but i belive was on nov 6th 2009...i had unprotected sex with guy # 1 on nov 26th...i had unprotected sex with guy # 2 on dec 12th and 13th...on the afternoon of dec 13th i took a pharmacy test and it came back positive but since i had a dark line and a faint line i though i wasent pregnant so in the morning of dec 14 th i took a plan b pill during the 72 hours window...later on that day dec 14 th i took another pharmacy test the same thing happend one dark line one faint line,, at this point i was very confused...next day dec 15th morning i went to a clinic and they gave me another test that came back positive for the 3rd time in the past 3 days...on jan 6th 2010 a ultrasound was done stating that i was 8 weeks and 5 days...questions...can a pharmacy pregnancy test show positive 48 hours after unprotected sex?..can an ultarsound be wrong by 15 days or 2 weeks during the first trimester?....would of the plan b pill definetly stoped the possible pregnancy?....

[Msc83]

Thanks for your answer Clysta?

[Clysta]

No, because plan b does have a failure rate. It stops ovulation. It doesn't abort a pregnancy, so if you had already ovulated it wouldn't have done anything. Early ultrasounds are very accurate and are normally not off by so much that soon, but it can happen. No a pregnancy test can not detect pregnancy after 48 hours. It takes at least 2 weeks to build up the hCG to show an answer, and even then you have a high chance of a negative. If you had a faint line, it's still a positive.