confused

Rebekah • Married. Mother of 1 Boy (3) TTC #2
Had EWCM for the last 4-5 days but didn't think to test with an OPK.
Did one this afternoon and there was a very faint line. I'm on CD23 so very confused. My cycles are normally regular 28 days with ovulation in the middle. 
Anyone able to give insight? 
Thanks