I was told by my doctor that i am pregnant last week, last night i did a clear blue pregnancy test and it said i wasn't pregnant what should i do?

Retest blood w/ doc: The pregnancy hormone, hcg, rises as the pregnancy grows, and falls if the pregnancy fails. So if you were having a miscarriage, the pregnancy hormone level would drop. There is also such a thing as a "chemical pregnancy" which is a miscarriage that happens so early, that there is never any visible gestational sac by ultrasound. Lastly, you could have a faulty home pregnancy test. Re-test by blood.