I was like that too, and got a reverse since highschool. I got under so much humiliation in middle school, and so many stress, that it kind of unblocked something in me, and now it's like: "talking to a random stranger? I already did way more stressfull, finger in the nose" What I can recommend that helped me as well, was to write down on your phone all the situations that you got in a stressful social situation. Then, before something too stressful like going to a party, read it and realize that you went thru already so much difficult situations