I think what you are trying to ask is whether a home pregnancy test would taken two weeks before it should work correctly would, in fact, give an accurate reading. The answer is no. HPTs look for the HCG hormone. It is not in a high enough concentration a week after conceptions (approximately 5 days before a period is due) to be detected by a HPT.
If you are on the pill, you should not have taken Plan B. Since you weren't ovulating and then took Png B, there is zero likelihood that you could have gotten pregnant.
Please, see an ob/gyn and get educated on how the pill works. how conceptions happens, under what conditions to take Plan B, and when and when NOT to take an HPT.