I would guess if it was urgent they wouldn't be telling you to wait until :
I would think this too, hopefully it is the case.
Your cervix is very dynamic and can shorten and lengthen often, even while they watch. They don't tend to be concerned until you are under 2.5cm and funneling. They would not do a stitch this late in the pregnancy as the risks outway the benefits.
Maybe just try and stay of your feet as much as possible to keep the pressure off your cervix.
I hope you can get an earlier appt or at least speak to someone to ease your mind.