dark, light then dark OPK?

jade

which do I count as my positive? I'm irregular so never know when i ovulate. this is only my 2nd time using opks (used first month but gave up using them. now on month 8). They started off light, got crazy dark (5th April was darker than control line) & then it got a bit lighter, but this morning's is still dark. I'm so confused!

^ Tests since 4/4 until this morning 6/4

^ the top test here was 5th April's first test.