You’re right, tbh I’ve had it a few times (before covid) and it went away the next day like you say. Il just wait and see. My appointment is at 9, so will have to wake up early to see how I am. so I can call them.I'd wait until tomorrow to see if it's still there.
I've woken up many times with a sore throat and it's gone the next day.
Obviously if it's still there tomorrow then I'd ring and explain and cancel your appointment.
I've seen many things that have said Covid in pregnant women has no affect on the baby unless it's during birth
I did read somewhere that if you do get it, the baby has immunity to it aswell as yourself.