37 weeks with dull backache should I go to the Dr.?

I'm 37 weeks pregnant and have been having dull to painfull back pain with l "twinges" (not constant pains but they make me say "ow!" when they do happen) for the last two day's.I've got a Dr.'s appointment on tuesday, should I wait till then or go to the hospital tonight if the pain doesn't stop? It's my first baby so I just want to check, thanks guy's :D