So, I've only done opks for 1 1/2 cycles (wanted to see how the ones at the end of my first cycle would look for comparison), and I personally think there are just too many darn variables, at least for me! How much fluid intake and when; what time of day; what number urine of the day... For me, the lines were just all over the place. I did some 2nd mu that were really dark, and some barely there, so I tried with 1st mu a few times ad most were darker in general, but some really light.
The way I understand it, LH is in your system all the time, and it can become more concentrated in your urine depending on fluid intake, so sometimes that could mimic an lh surge if you were a bit dehydrated.
It may help to track using other methods like temping if you're not already. Which is what I *should* do...but I'm probably too lazy to keep at it properly.
I did plan to chart BBT but when I looked more into it I figured it probably wouldn't work for me as it requires you to have had a certain amount of solid sleep and to wake up and take your temp at around the same time every day. But as DS still wakes up in the night or I usually wake up needing the loo or a drink etc I don't think that would be much more reliable than the OPKs!
ugh. 
I think I'd struggle to enjoy that tbh and I don't want this to turn into a complete mission unless obviously we struggle and have to step up our game. Hmph. Feel a bit overwhelmed at the minute.
