I'm in the same boat, My doctor sees his CP patients every 28 days, so I have to wait until the day I am out to go in, sometimes I forget to make the appointment as I am leaving, and have to call, and all they have left is late afternoon, so by then the pain is spiking.
Dont be afraid to be a bit pushy, everyone forgets things once in a while, Its perfectly okay to call and ask if they can make an exception for you this time and put a rush on it and get it this afternoon. I have had to do that, and they will do it if you ask.
Hang in there Lee!
Your Friend, Fabby