I am so sorry to hear this.
Usually, going a bit nuts gets an appointment. Sorry, but it has done for me in the past.
You should not have to wait till next Tuesday, they are having a giraffe. Anyone would go out of their mind by then.
I insisted I get scanned when I mc'd as they told me there would be a wait. DH got a bit shirty on the phone and I was in that afternoon, though I did have to wait with peeps having 12 and 20 week scans as the epu was full, I didnt care, i just needed to know.