Opks after trigger

So after my trigger all I had was opks in my house and I wanted to make sure my trigger worked since I had to travel with it. Well I tested and it came back neg. Well I've used about 6 all neg. except one pos. the night before my IUI.... I've done an hpt since to ensure the trigger worked and that was a BFP. But everything I've read online says that the trigger should have made the opks pos....

Any thoughts? I'm kinda curious if the ones I used were accurate somehow.