I think you can miss the LH surge with OPKs. I don't always get ovulation pain so I tried them and I was getting negatives when I had the strongest ovulation pain of my life. I don't know much about OPKs though. How many times a day are you testing? I think different women surge at different times too. I was doing it twice a day to see if I could catch it and they were getting darker but still negative. I'm still doing them out of curiosity and they are getting lighter so it looks like I must have missed it. Not sure I will use them next month if we aren't successful this month.
My 3.5 year old obviously doesn't know we are trying for a bub, and she just came over for a cuddle, patted my stomach and said "you have a baby in there now mummy. We are calling her Charlotte"
I might take it as a good sign even though it's too early to actually be pregnant