I've been doing OPK's, the cheap ones from Amazon since Wednesday. I have an irregular cycle and have been off Cerazette since December. I'm not convinced I'm ovulating at all so have been testing regularly since Wednesday. The 25th is 14 days before my next predicted period. All of my tests have shown the control line and two have shown a very, very faint second line. I read that urine concentration can effect the test and as I drink a lot (like 4+ litres of fluid a day), I refrained from drinking more than a few sips today before I tested at about 3pm, the urine was more concentrated. I went about my business and forgot about the strip and when I checked it about 25 minutes later there was a clear second line, not quite as dark as the control but close enough. Stupidly I didn't take a pic. I tested again this evening after drinking my usual amount and with my usual watery urine and there's no second line at all. Could the test earlier have been positive or am I just getting my hopes up? I'm very new to this.