@SarahWalker,
Is there any teaching hospital anywhere near you - even a few hours drive a way? Lots of university hospitals are teaching hospitals, and they have clinics, and mine near me has a gastroenterology clinic.
When I first moved from California to New Mexico, I badly had to get my eye pressure checked (long story) and I called UNM eye clinic and they wanted to give me an appointment in a couple of months, and I was persistent about a complicated eye history and immediate need, and they got me in the next week.
I see you are in Canada. I'm not all that familiar with what you can do there as a patient-with-friend team, but maybe.
There was one other time I bulled my way into being seen, that when I was in a city I used to live in and moved from, and was back there getting a mammogram and regular gyno visit. Turned out the mammo was positive and I wanted to be see there instead of the new small town that was several hundred miles away, for the biopsy. I argued and argued at the breast cancer desk and finally the head administrator type said ok, if you will wait.
(I'm ok, that was almost 15 years ago.)
Another poster on a2k is a similarly strong minded broad re medical situations, to good effect. What to say, be persistent but courteous at the same time.