Still new(er) to this opk thing- HELP

So I had a positive opk the 5th and 6th of March. We did it on those to days, skipped the 7th, and then again on the 8th which said it was ovulation day. What should I have done differently? Also, is it still too early for a positive with those dates? Bc my test is negative but I’ve been crampy, which is how I was with my first. TIA!