how do you get around the paradox of having to talk to somebody about the fact that you cant talk to anybody?

I havent been on this website for years, but i had quite a bad day and want some advice, so excuse me if this isnt quite within the etiquette of posting on here. Ive been dealing for years with what i guess i would call extreme social anxiety. Its caused a lot of bad things for me unfortunately. 

I try to find generic advice, but i seem to be a bit different from what people generally seem to regard as social anxiety. I dont really feel all that insecure, and Im not worried about making people like me, and I understand social cues--it feels more like a physical response to me, and I go almost mute. Its like i completely shut down when i have to talk and even knowing what i should say the words will not come out, meaning ill say "i dont know" when i do, if me explaining would take more words, for example. If i have to speak with too many people in a row, or do something i was not planning on, i start to cry and it is very hard to get myself to calm down. I am always worrying im not where im supposed to be, or that im breaking some rule i dont know about. 

I really need to seek out help about this, as helping myself hasnt been working. I dont want to be someone who makes people uncomfortable crying over very small things, especially at work. 

Problem being, I have tried going to doctors twice now, and both times been told they werent able to help me... I understand that i cant expect them to chase me down and beg me to participate if im not even able to meet them halfway and tell them why i was there. But in the one instance, the woman told me, even after i had tried telling this to her, that there is nothing she can do about not talking and that unless i can outline exactly why i answered what i did on my screening test and what i want her to do about that then theres nothing she can do. The other time, i think i might have just been somewhere with resources not suited to my problems, as i was told only that there was a group coloring and sharing session and i should come back some time during one of those T_T 

Is there some specific thing i should be saying? The idea of even setting up the appointment terrifies me and I dont know that id even be able to get the words out should i actually get to a professional, but its really terribly wrecking my life at the moment.