Two suspected ovulations dates - based on the following, which one was ovulation?

Hi all. I had a small surge on an OPK last week and on Friday had EWCM so on Friday and Saturday we BD'd. This would have been CD 17 and 18. However, today (CD 21), I have been having very watery CM today (not EWCM) so thought I would just see what an OPK said. It came up as equal strength to the test line. So based on this, when did I ovulate?! My DH is away now and I want to cry as I had been so excited we caught it!