she left you an opened pregnancy test??? i wouldn't trust the results anyways just for the fact you didn't open it yourself. get another test....read the directions (depending which test you get there could be 1 line, 2 lines, positive sign, negative sign, a smiley face, a frowning face, says PREGNANT or NOT PREGNANT) so get another test open it yourself and retake it.
I don't think keeping it leveled would really affect your results. However for your piece of mind, just take another test.