Equate OPK test... Some help would be nice

Anyone have terrible experience with them. My first time using them or any OPK test for that matter. Though, I started taking them yestersay, because, glow is saying this is my possible fertile window. Though, I took 2 yesterday. One was like barely colored and the second one got a little darker. Then this morning I took one and its fainter than than the one from last night? I think glow is accurate on when I ovulare, because, I just recently had gotten pregnant a few months back and it said I estimated conception on April 6th. Right when my fertile window was predicted by Glow. I'm so friggin confused. I am in tune with my body and I just personally feel like these test are a flop for me at this point. Or should I just give it time. I do follow the instructions to the T by the way.