HELP! Mid-cycle bleeding but neg OPK

Amanda • Trying for baby #3!
Help...I have had very light dark brown spotting today. I always get this mid cycle of a very regular 29 day cycle. I decided to verify it was ovulation bleeding using an OPK and it was negative. Now I'm a little confused. Did I miss the LH surge or have I not ovulated yet? I'm worried I'm not ovulating at all.