I was exactly the same. I used the cheapie green and white sticks and on the first day of using them I got a feint test line as well as the control and then the following day, the test line got somewhat darker. The two lines NEVER got equally dark so I missed my surge (in a 12 hour period). I kept testing every day for about 2 weeks after that and never saw another test line.
Therefore, I would say you have missed your surge with the test strips as your surge may only have lasted for a few hours. It does show however that this is your ovulation time, so you haven't missed that.
If you keep testing for a few days (say 2) you will most likely find that you won't see another test line. I would do this as a reference for yourself for this month anyway, but no more after that or you're just tormenting yourself and wasting your test strips.
Best of luck.