Do you co-sleep? We never planned to (didn't plan to do AP either though!) but around 5 months is when we started co-sleeping due to exhaustion. DD would do the same thing wake around 12 pm or 1am. I'd start her out in her pack n play basinett then at her first waking, nurse her and bring her into bed with me. She slept longer cradled next to me in my arms. When she would wake again I would latch her on and go back to sleep. it SO helped me get through those frequent wakings. She still sleeps like this right next to me and when she wake nurses and goes back to sleep. Teething can cause more frequent wakings. I also got DD an amber necklace around 6 months old which seemed to help. Recently she had it off, then she started tossing and turning and waking more. I put it back on and she slept better again!
I forgot that she was teething for her canines!