Question on ovulation

Glow is telling me that today is the most important day to have intercourse. However, I took an opk test on Tuesday and it was positive. The instructions on the box tell you that once you get a positive you don't have to test anymore. I've also read that once positive you should be ovulating within 12-36 hours. My question is does that mean that I ovulated on Wednesday/Thursday and I'm no longer ovulating? Feedback greatly appreciated!!