Kinda freaking out..

Haley
Okay! So, my period is due on the 5th, ovulated on the 18. I miscalculated my ovulation at first and took too hpts too early and got both negatives. Today my roommate brought out an extra test she had so I took it. It was the New Choice dollar store brand. It was the first time I've used this brand. I followed the directions, but four drops of urine on it, and immediately got the positive line and control line.. It lasted for about thirty seconds.. Then the positive line faded away.. Has anyone had anything like this happen? (I haven't!) could this just be a faulty test, an evaporation line, or perhaps not enough hormones in my urine? I plan on getting another test and trying in a few days, but in the mean time, I need some opinions.