Hi Misskylie, I think if it gets higher they will suggest you stay for a few hours so they can monitor you regularly over that time? I had a similar thing, though later on in my pg. Each time I stayed, they monitored me over the course of a couple of hours and both times it was within normal limits after an hour or so. I was never conscious of being anxious about going to see the middies, but I still had that white coat syndrome...
Hope all goes well for the rest of your pg and that your bp behaves itself.