I'm so confused!!!

So I've been tracking my ovulation for 6 months now, but my husband and I didn't start REALLY trying to conceive until this month. We had sex 3 times during my fertile window, which was last week (according to this app). Well, I just noticed today that I have what I THINK is cervical mucus. Maybe I'm doing too much reading, but doesn't CM mean you're fertile?? If so, why is it happening so much later than 14 days after my last period? And is this app wrong?  I need answers!