I know the obvious answer is go to the dentist but doubt they will do anything. I had a cavity in a wisdom tooth of all places back in April and was told to wait until December before it could be taken out. Never had toothache it with it ho just an irritated gum. This feels different but it seems to move about. Have tried oragel and that dosnt work. Plusni dont get it Everyday. I'm 37 weeks as well and really fed up and emotional for some reason 
Not sure what I want anyone to say , list needed a damn good moan.