What's going on?

I posted a few days ago but nothing has changed. Looking for further advice.

I've recently come off the pill (2 months ago). I decided to try and track ovulation this month with OPKs. I've been tracking since CD9. I'm STILL getting very faint lines and nothing close to a positive and I'm now on CD 17! When is the latest you can ovulate in a typical 28 day cycle? Do I keep tracking for ovulation until I'm supposed to get my period? When's the earliest you ovulate?

Sorry for all the questions! Newbie at TTC and still trying to get a handle on things.