I just want to add that it's not at all unusual to test and have a feint line. This is because the LH that the opk detects is ALWAYS floating around our bodies. It is at the surge just prior to ovulation that the large amount of LH is released. This is depicted by a very dark second line. I often don't get a true positive either and I do ovulate as with Keen this is verified by blood tests.
However I will often test and get a feint line days away from ovulation. JUst prior to ovulation the line becomes more prominent and then on ovulation day it is quite dark or the same colour as the control.
Good luck in catching that egg!