34 weeks and have a pain iv never had before

I carnt really explain it as its a weird pain this is my 4th baby and never had it before its a dull aching pain in the bottom of my back at top of my bum that comes and it comes witha very weird aching pain gets stronger then goes.. its not like labour pain its a pain that takes my breath away.. anyone else had the same went ro docters and she just told me it sounds normal but it isnt normal iv never had it before i felt so pissed that she didnt check me over.. im high risk so she should of checked me and she didnt..