I need help with OPK.

I need help. This is my first month doing the ovulation kit. According to the instructions in the box, my CD to start testing should've been on CD 8, I started testing that day, it's been 10 days and I have not yet seen a positive/peak day on the stick. Is it normal for it to be more than one box that you have to do this, one box includes 10 test. I'm doing the Clearblue Advanced. I did see one time where the test line was dark, but not as dark as the control line, but then the next day, the lines have been getting lighter...so did I miss? I've been testing every single morning. I'm so lost and need help. Thank you!