Hi there. I am currently using OPK tests (first month of trying) and used them last pregnancy (got pregnant that first month of trying). I kept a diary of my opk tests results last time and seriously dont go off a faded line. Some days the line was 1/2 as dark as the control one and the next it was barely visible. I knew there was a result when there was a really good second line (tho saying that I went and got a clearblue digital to confirm the results) just keep testing. You will know when you have a second good line. Oh what tests are you using. I use cheap internet cheapies. The test line on those doesnt have to be as dark (from experience) but nearly as dark if thta makes any sense.

Goodluck!!!