..it's just thinking of what he's going to say and the fear of that, when the likelihood..(and as your friends have said..)..is that he wont be saying that at all but that's your worst fear..(our worst fears are hardly ever the thing s that turn out though..)...so your head has already got to the GPs and is terrifying you, that's too big a thing for you to be able to cope with Sam...the being in that surgery or waiting room...it's just too overwhelming for you so it's breaking it down into pieces and steps that you can cope with and without those fears...each step you take and each piece broken off that 'head monster' will weaken it and make the next step more easy to cope with because you're starting to take control of your fears..../putting those fear bitches in their place...
..and the you'll be called/your name and you'll be in with the GP and talking to him/her and he/she will be reassuring you that all is ok and nothing at all to worry about...
..and then you're in the waiting room, there is nothing to fear in a waiting room, no one will even speak to you in there, you're just sitting in a room and nothing more, so don't think beyond that..(take a magazine or book etc to focus on while you're sitting there..)..(I'm not sure, can you listen to your music in waiting rooms as well..?..)..but no matter if not, because you're just in a room, reading a magazine is all...
..so, then you've got there and there you are and the door of the surgery/waiting room...all to focus all of your thoughts on is opening the door and walking in/that's all and nothing more than that...you're just going through the door...
...try and focus and think about your steps if you're walking to the bus stop/train station or if you're walking all of the way etc...don't thing beyond each thing that you're doing/your whole routine from waking up to getting there...only focus on the 'now' of hat you're doing...
..Sam, try not to even think about it atm until the day you actually go/that's soon enough..you have made the appointment now, so you've done all that you can for now..and well done you/feel proud of yourself.....