Another clear neg opk

I really don't understand....I see all the other opk pics from other posts and they all look much darker then mine....and I've added my log for today and Glow has dropped my chances of ovulation and pushed it all back a day...so instead of going from the 12-18 it's now 13-19!! Im testing first thing in the morning, should I test twice a day? Or use different opk's? I'm starting to loose hope that I've missed out this month....hubby works away a lot, so we only have a short time to b together!! Feeling abit low today