This is my first month using opk's. I felt pretty confident in knowing right around when I O'ed before just by CM. so this month I started using OPK strips on CD 13. (Today is cd 15) I was due to O yesterday or today and had EWCM yesterday but negative opk. Today I got a slightly darker line, but still lighter than the control....but EWCM is gone. I think the opk's are confusing me more than helping. Now I feel like maybe I somehow missed o? But now glow updated and says I won't O for another 2 days? Ughhhhhh