I'm trying to understand the dates that you've given us... Cycle day (CD)1 was boxing day, and you had unprotected sex on CD3, right, when your period was almost over. That would make you CD 14 today (Monday), is that right? And the nausea and vomiting started on CD 8?
I'm confused too... but then I re-read this bit...

... I had my period on boxing day just past & two days after when it was almost over we had unprotected sex with me knowing its not impossible to get pregnant on your period although unlikely. On Tuesday there just past (5 days ago) i woke up feeling fine and was getting the bus to work when i felt waves of nausea...
So you DTD two days after AF had finished? Is that right? Which was Tuesday 5 days ago... which would have been Tuesday 3/1/12? Which mades it CD9.

Semen can live for a couple of days... so it is quite possible you are pregnant! And it is quite possible that the test won't show up positive until after your period is due!

ETA... wait, I don't think I read it right either! When did you DTD?