It's been my first time of using them this month too - they've been stressing me because I thought I wasn't ever going to have a second line, had my first faint one yesterday (day 14 of 26 / 27 day cycle). And another this morning, am hoping it will be darker tonight.
Because I didn't have a line before yesterday I'm hoping that means I'm having some sort of hormone surge or the beginnings of it. Using that logic you've probably done the right thing anyway (although that's my logic and I'm new to all this!!!).
Hope it's worked for you
