Ok so I have been testing with opk's for the past three days. Yesterday only had the faintest line. Barely even visible. Today had a def line, but only half as dark as the control, so according to the instructions it is negative. I'm in the uk ATM, just so you keep that in mind. I took the opk about 6hrs ago. It was about 4pm. So what I am wondering is, should I consider that the fsh has started to flow? Could I miss the surge? What is the best way to do this?