Looking back at my tests they did darken up until Sunday. Sunday afternoon it was almost the same colour, but not quite.
But when I tested yesterday night when I got home from work it was blank, like no line at all so that could be that maybe I missed it .... Now I wish we had more sex. but I was sooo tired I just wanted a break!!!
They are also new OPKs - I used a supplier from the UK because I really wanted to try Conceive plus, and couldn't find a Canadian provider - so I was testing a few times a day with the new ones on the weekend to see if I could see changes throughout the day, and I did so I know they aren't bad strips. I cant at work, it is too weird so I just tested when I got home around 6pm.