I do something similar, and am not fully aware of it. My husband has told me this a number of times. I liken it to a glass see-through wall, of sorts. Like I'm there, and trying...often even very hard...but not really truly opening up. For me, it is definitely a protective mechanism. In my particular case, I can even come across as extremely outgoing. People have used the word "expansive". In my case it's almost like I get a nervous "blip" of hypomania. Not sure how much it is hypomania for that "blip" and how much is an anxiety reaction. Likely a lot of anxiety mixed in. A lot!