Did I miss my LH surge?

My husband and I decided we want to ttc a few months ago (yay!!). I stopped my birth control pill in August, and my cycle started right away, I've always been very regular with 28day cycles.
So, this month we started using opks, and I am throughly confused!
I stared using them as soon as af ended, and have been testing in the morning and at night every day. For the last five days I've been getting a faint line ( I know it's only positive if the line is as dark as or dark then the control line), but no clear positives. Yesterday morning I did not test, I was late for work. I tested when I got home from work and the line was a lot darker than anything I've gotten so far, but still not a clear positive. well, I tested before I went to bed and it was very faint. 
Is it possible that I missed it? Should I keep testing? Any advice is greatly appreciated! 
Baby dust to all you beautiful ladies 😘❤️