Ugh!! No surge yet (AF due 4/4-4/7ish)

I am supposed to be in my fertile window and my peak was supposed to be 3/19, did not have surge Sat or Sun, and no surge this morning (Monday) either :( I am using Internet cheapies and the darkest it has been was on 3/16...thinking of getting the digital Clear Blue to see what it says tonight/tomorrow...otherwise will get blood to test for progesterone later this week...feeling very discouraged because we have been BD practically everyday and flooding the field with swimmers, but if I didn't/don't O it's all for nothing :( fx for a late egg or earlier missed surge!! Anyone have this happen to them?