Kaz, my first HPT was a digital one and it said neg, but when I pulled the actual stick out of the digital reader I did notice the faintest of lines. I didn't think that it meant anything and carried on thinking I wasn't UTD. But when AF didn't come for another 4 days or so I did another one and the line had gotten stronger. That's when I went in to shock. I was convinced I wasn't UTD until I did 4 tests over a week, each time the line getting stronger.

Good luck with the next test!