Isa, I can certainly relate to what you're saying.

IMO, if worrying about this is causing you stress, then it is certainly worth calling back the clinic/centre and saying something like, "Look, I'm feeling a bit anxious about this and would really prefer to come in for the scan/monitoring before I'm 8 days overdue, just to reassure me. When can I be booked in before then?" It is a completely reasonable request, I could save you a LOT of unnecessary worry between now and tuesday (I was the same- DD was 5 days overdue and at the scan they found her fluid levels were dangerously low, and induced onthe spot. So now that my DS is 10-11 days (!!!) overdue, I asked for monitoring and an U.S. close to 5 days, just for reassurance. And I felt very comfortable about doing so. He's fine- hence still being inside me!- and the scans did a HUUUUGE amount to put my mind at ease).

And that sorta stress isn't good for you or baby. So if you're at all worried, my advice would be to call the midwives back and see if you can get it any earlier. your bub is probably completely fine, but you sound like you'll cope a lot better if you're reassured.

Good luck!!