frustrated with OPK

A friend gave me a pack of First Response opk that she had purchased but got pregnant before needing to use. I figured I'd try them this month, our 5th TTC. I started using them on Day 9 and today is Day 13, so I have two tests left but have seen no surge. Glow predicted today as my most fertile day. It's super frustrating, and reminding me why I was hesitant to try opk. Just venting I guess. I'm worried I missed the surge, or that it will happen after I run out of tests. Am I overthinking this?