Positive? evaporation line? i can't tell.?

i took a htp this evening. first reposnse, non digital. initial result was negative. after 3 to five minutes, knowing myself, i decided to take the test apart so i wouldn't be tempted to keep taking it out of the trash to reexamine it. when i removed the results strip from the case and was about the toss it out i thought i saw something. it was almost a mirage. i had to hold it up to the light to see it and even then i thought i was going crazy it even seemed colorless but it was there. i have been watching it for an hour now and it has grown ever ever ever so slightly more visible so that now it is unmistakable. faint, thin, but there is no mistaking it is there. if i hadn't seen the beginnings of a hint of a line within the ten minutes after testing i would have dismissed it as an evaporation line and let it go. i don't know if what i saw at first was merely the shadow of the unresponsive dye strip which has since become an evaporation line or if i saw the beginnings of a faint positive result. my urine sample was very light. i drank a lot the afternoon and my period was due today or tomorrow so the hormone level in my pee, if there at all would have been slight. i intend to retest first thing in the morning, but i can't stop staring at this test. it's making me crazy.