You should TOTALLY Be charting BBT. And use OPK only as a cross-check to your BBT and CM. It's really easy, especially if you sign up at
www.fertilityfriend.com Plus, then we can look at your charts and help you decipher what is happening with you.
If you are breastfeeding, that will mess with things too...
But if you aren't, then I suspect that your ovultion has been delayed due to stress...probably stress over TTC and DH being gone a lot! Is this a possability?