My bub was like that all pregnancy and then turned right before labour and then turned back to posterior again in the car on the way to the hospital during labour. I ended up with syntocinon to move things along, vacuum to turn him during pushing and then forceps delivery. He was 4.2kgs and 38.5 cm head and the cord was around his neck. I'm not trying to scare you, everything was fine, I guess my point is the little buggers can just turn last minute and throw all the plans out the window!
Make sure you rest up.