stupid opk

I have yet to master the opk's. My cm and temps are telling me that I am about to ovulate. But the stupid test keeps giving me negative. So I will go to the drugstore today and drop some more money on the tests. I am on CD 16. I usually ovulate around CD 19, but this month I did a round of Clomid. Will this make me ovulate sooner or later? Meanwhile, I feel crummy and not in the mood for love. Last month I o'd on CD 17, but I also had an SHG on CD 10. My last pregnancy I used the OPK and I thought I missed my o b/c I never got a postive OPK, but then I on CD 31 I had a BFP. The test should not be this difficult for me to read. Another I am mad about is cancer. My secretary's mother is dying from cancer. She is riddled with it. This is the third person in the last six months who has been diagnosed with terminal cancer. Two of my good friend's fathers and now my secretary's mother. It's so awful and sad and frustrating. Damn cancer....