Ovulation?

A few weeks ago, I was at good ol' Wal Mart and my husband and I were looking at ovulation tests. I was (and still am) convienced they are NOT worth the price! But though I argued and argued, he talked me into buying a box of tests. 20 strips, directions, and a urine collection cup set me back $20 AND THAT WAS A CHEAP ONE! To get on with the story, I am 17 strips into these tests and according to the them, I haven't ovulated. Really? I have no hope for these last 3 strips. I mean, really! I really should take everyone's (including my mom's) advice and quit worrying. They tell me "thats when it will happen!" We'll see!