There is no negative line on an HPT. If the other line showed up, even faintly there is a strong possibility you are pregnant. Good luck =)
Some tests the negative line shows up light...I know with EPT the +/- test my negative line was lighter than the control line every time I used it. I would suggest waiting a couple days and going with a First Response or a Clear Blue Digital.
Chances are if the negative line was faint the test hasnt worked properley, but then some people say a negative is still a negative. If i were you, to put your mind at rest, i would test again with first morning urine :-)
Goodluck
x x x