Ovulation sticks still negative!

I need y’all help please! Calendar says I ovulate on the 18! Test keep coming back negative but chart says high chance of pregnancy today, if it’s so high why am I getting negative opks? Idk I had a tubal reversal June 2 and my period fell for four days starting June 5, and my doctor didn’t give me a time frame to start trying to conceive. He said u can start a week after surgery if ur up for it and I was up for it three days after my surgery!! Idk I’m dying to give my fiancé his first child!