So this is the first month I've used OPK and I was expecting to ovulate in six days. Thats what the app said this morning so when I got a high I was kinda expecting it. So I tested back a few hours later just to see where it was at and it said low again and now that high I got this morning is my peak, now I'm supposedly ovulating tomorrow. Am I doing something wrong?  Can someone help me understand this?