Pricking feeling??

[locket]

Hi I am 38 weeks pregnant with second child and every so often i am getting a really bad pricking feeling down below especially if I am walking- I have to stop as it takes my breath away! If i am laying down it feels like kicking really down low.. My midwife told me the baby is engaged. has anyone else had this? My waters never broke naturally first time round so I was wondering if they were nearly ready to go??? x