OPKs are tricky. OPKs tell you when your LH (lutenizing hormone) has begun to be secreted. Some tests are more sensitive than others, some require higher levels before reading positive. You can test positive for LH for a few days and then not ovulate till a day after the last positive. Or you could test positive and ovulate within hours. As well as anytime between! Or you could test positive and not ovulate at all. Or you could test positive and then have another LH surge down the road and ovulate then instead.
Bottom line is OPKs take some getting to know your own body and some interpretation.
When I use OPKs, I use inexpensive bulk Wondfos so I can take several a day once I get a positive and keep testing till the day after the positive goes away. Then I also watch for a temp jump on my chart to confirm ovulation.
Gooood luck! At the very list try to BD two or three times over the next three or four days (providing your other half has normal sperm).