Chance of getting pregnant if OPK not positive for a few days?

I am just learning a little about OPK. From what I read on fertilityfriend, "typically" you ovulate the day after your surge/positive OPK even though I know it can last from 12-36 hours. But If I take that info, would i still have a decent chance of being pregnant if we had sex yesterday but I don't get a positive OPK for another day or two?