help please! opks

Heather • 💙Otto Wayne 9/7/18 💙💚Owen David 5/22/20💚
This is only my third time using opk's and I've had different patterns every time... the first time was in October I had gotten a positive twice 10 days apart (we were pregnant at the time so I'm thinking that was the reason for the second +). The second time was last month, it was a normal positive cycle....  however, this month I started clomid... I'm around the time I should ovulate and so far this is as dark as it's gotten- 
But now it is getting lighter and lighter (I tested three times that day- morning, afternoon and night & the day before was lighter morning and night).... is it possible for the test line to not get as dark or darker than the control and still be positive? OR is it possible to get darker then lighter and and then darker again? OR if it doesn't get dark again does that mean my levels didn't get high enough to ovulate? Does clomid effect the test?
Please help if you have any insight! Thank you!