Oh Julia, this is SUCH rotten luck. What hopeless organisation on their part. Were they apologetic?
I don't know if it's right, but I'd take heart that it's not anything desperate as otherwise they wouldn't have pushed back your appointment. They could just be being ultra cautious.
The waiting and the uncertainty is just the absolute pits. When are you having the ultrasound? Try to take it one day at a time, focus on the now and distract yourself as best as you're able. Let us know how you get on. And write a letter of complaint about the useless admin... K xox