OPK question

Sia • First date: Oct 29 2011. He asked: July 29 2012. "I Do": June 29 2013. Mommy and Daddy to a son and 2 daughters. Maybe one more??

Ok ladies, I'm just wondering if anyone has experienced this:

Have you ever had days of opks in a row that never even registered a test line? Aren't you always supposed to have LH in your system that should show up on an opk?

My test lines (every single one, for at least a week) are so faint that they remind me of indent lines.