If i take the blood pregnancy test and it turns out negative, would there still be a possibility that i am pregnant?

Unlikely: There's a possibility only if the blood test was done much too soon. Can do a home pregnancy test 1-2 weeks later. A urine pregnancy test done correctly gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened) or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon.

That depends: on when a pregnancy test is done. Had you missed your period when it was performed?