Actually guys, from peeonastick.com, I learned something quite interesting.
There are two kinds of blood tests, qualitative and quantitative. One measures the quality of your blood, and the other measures the exact amount of hCG in the blood.
Blood tests are normally LESS sensitive than the pee ones, because women are normally quite pregnant by the time they get the blood test. Personally, I think it is far more likely to get an early negative blood test and a positive urine test and still be pregnant!!
So my advice is this: Wait 2 or so weeks, and then go get another blood test done. Do a few more urine tests as well to confirm via them that you are indeed pregnant.