Another OPK question?

DH and I BD'ed on CD 12 even though I didnt get a + on the OPK but I had loads of CM and figured what the heck because I usually O on CD 14. I then got a positive then on CD 13, CD14 and today CD15. Hubby was out of town so we couldnt BD. If today is CD 15 and I am still getting +, should we still BD and what are the chances of the CD12 attempt? And how can an OPK give a + for 3 days? Does that mean I am O'ing now or all this time means its still coming? Sorry to be so confusing.