31 weeks and badly in pain & confused 😪

So I'm 31 weeks I've had this on & off hip/tail bone pain since 7-8 am this morning so about 6 hours now... it feels like it changes sides as it comes & goes... it was just an uncomfortable niggle to start with now it's quite painful my tummy isn't tight or anything... I've tried drinking water & changing position but nothing helps when the pain is there... I have an appointment in 2 days first thing & I'm not sure if I should wait it out or go to be seen... or is anyone else experiencing this?

My last natural labour was 4 children ago so nearly 10 years so I really cant remember what contractions feel like in the beginning.. with my last 3 I was induced due to them stopping it from starting as waters broke early... & when I'm induced I go from 0-60 pretty much in active labour & delivery happens within minutes so lots of pain but this feels a little different to that.. thanks for everyones advice ❤