Long cycle confusion

I have a average 40 day cycle. I took an ovulation test on the 19th and it was not quite positive but I didn't understand at the time. I would be 4 days late AF due 5/3. But I think I'm having a 56-58 day cycle like last cycle because I just got a positive ovulation yesterday and today. Weird thing is if I'm ovulating now my due date puts me at my fiancés birthday