"Disgraceful"

I have been trying for the last 1 month to get a nurse appointment for my depo injection, however, everytime I go to book this they have no appointments available, and get told I have to wait a month, baring in mind I am overdue by 4 weeks now and I have informed them of this. They advised me to go upstairs on a Tuesday evening between 4.30-7.30pm, which I do so as I urgently need it, I waited over 2 hours to be seen just to be told "sorry we've gone over our time" so I had to walk away after 2 hours without having it done, baring in mind the injection it only takes 2 minutes. If I now get pregnant, as I'm trying to take every precaution I can not to do so, on this practice head be it, I will be taking further action due to this. I should have faith in my doctors surgery to protect me from things like this occurring.