positive OPK!?

CD17 and first round of clomid. Went in on day 12 for an ultrasound and showed 3 good size follicles. She thought I should ovulate about 2 days later...here we are 5 days later and this is the darkest I've seen BY FAR. (The rest were squinters) is this a positive opk? Anyone else ovulate late on clomid? Hoping this is our month! They have us on timed intercourse so that'd be yesterday and again tomorrow! (They suggest every other day)