:smt039 Lizzie,
It can certainly be frustrating this TTC journey. I too use OPK's and I'm on CD27 and am yet to get a positive OPK or ovulate ](*,) .
How long have you been off the pill? As your body gets used to functioning by itself (without the pill) your cycles can go a bit crazy and erratic. You could be having a long cycle. How's your CM? Fertile?