OPK.. did I miss it? Or did I test early?

This is my opk from CD15 @ around 7am, DEF negative, I know..

This was my opk on (technically) CD16 at 3:30am (I work night shift lol) and I was super excited I was almost there!!! Hubby and I had sex about an hour before I took this test

So, after I went to work later that day (still CD16), I was curious and checked to see if my opk got darker and well... it was SOOO negative!!! Did I miss my ovulation while I was at work?? Or did I maybe ovulate before the positive-ish one on CD16 and not catch it?? Any chance my hubby and I did it at a good time?!