Anyone have a 33 day cycle?

Amanda • I`m 28 years old. Married since 2011. We have a 5 year old son. Baby #2 due in nov2016!
Just wondering if there's anyone with a 33 day cycle who's a little more experienced than me? I keep taking OPK's and they're an empty circle so my fertile days just keep shifting farther and farther every day. I'm on CD18, with no sign of an LH surge, SO is kinda bummed. Any info or help? TIA :)