Any tips on how to stop being shy?

Im trans FtM, I already came out to my friends and everything, but im very very shy when I try to tell a teacher to call me by my name, or someone else that's not my friends, to be honest, most of my friends just deadname me, and they already know I don't like to be deadname, im starting to think I should genuinely ignore everyone that calls my by my deadname, but im not sure...

Also im feeling dysforic by the fact of having to go to the girl's bathroom, i mean, not crippling dysphoria, but it's getting to a point where I sometimes don't go to the bathroom just because of my dysphoria, and I have a UTI because of that.... heheh. But I can't really do anything because im shy, and I don't know what to say to the school's coordinator (im in a school where a person has to coordinate the bathrooms and mostly every situation, checking who goes in, at what time, etc.) I really need to do something about it because it's a problem now, and it's affecting me.

Any tips?

(Sorry for bad english, im not a native speaker ;v...)