Did I not ovulate this month? OPK faint lines

Brooke
Has anyone ever not caught their ovulation time even while using opk?
Last month was the first month my husband and I started TTC. I started using ovulation tests and once glow said I was beginning my fertile window, I took a test every 12 hours. First few were negative and then a couple days later I got a faint second line. 12 hours after that I had a full second line and that's how I knew I was about to ovulate. Worked great but clearly not great enough to get pregnant
This month, I tested a couple of days into my fertile window right before my peak day - once got no second line, again 12 hour layer on peak day morning and got a faint line but it was almost as dark as the first line. We had sex that night and before we had ads I took another test and the line went away! We still had sex since they say you ovulate 12-24 hours after your positive test.
It wasn't a full positive but we did it anyway.. Did I miss my ovulation? Did I not ovulate or did I just have a slight issue with the test and maybe that was the time I was ovulating?
The test says a faint line is negative... Did we miss this month ? :( We still tried, but I hope these tests work! 
Anyone have similar issue? Hoping for no AF ! This is the last day of my fertile window