Positive opk last night and this morning, negative tonight???

Megan

First is from last night around 6, second from this morning at 9.

We had sex last night, I’m wondering if we should again tonight and even possibly tomorrow? But I’m confused. Got the dark line this morning an then came home to barely get a line at all. Is that normal? I held my pee for at least four hours before testing but am confused as to when I ovulated