Feeling weird when people use the pronouns I want.

So I’m trans I’ve been out for few people( non of them family cuz I live somewhere where they don’t believe that it’s valid). I pass as a guy very very very often pre T. I get really happy when I do and when I see that some people are respectful enough to understand it and immediately start using he/him pronouns.

But for some reason I get this weird shyness inside of me when someone does and idk what’s the reason behind it and why is it so powerful like that.

On the other hand. I don’t like when people call me with she/her

I’m usually very open and honest and social and accepting person. And for some reason once I hear someone other than my gf using that ( friends, colleagues, ext) I get very fast heartbeats and I get speechless a bit

Does someone knows the reason behind this?