ovulation tests

I use the clear blue ovulation tests and never seem to get a smiley face letting me know about my LH surge. It's getting very discouraging especially since I have about a week and a half before my next menstration. I have 4 kids from my previous marriage and my fiancé and I would love to have our own but it just doesn't seem like it will ever happen. It makes me wonder if I can even get pregnant now. 😞